Water Pollution


Water pollution, the release of substances into subsurface groundwater or into lakes, streams, rivers, estuaries, and oceans to the point where the substances interfere with beneficial use of the water or with the natural functioning of ecosystems. In addition to the release of substances, such as chemicals or microorganisms, water pollution may also include the release of energy, in the form of radioactivity or heat, into bodies of water.



 Water Resources of India

  1. Surface Water Resources
  2. Ground Water Resources

Surface Water Resources

  • There are four major sources of surface water à These are rivers, lakes, ponds, and tanks.
  • The mean annual flow in all the river basins in India is estimated to be 1,869 cubic km.
  • However, only about 690 cubic km (37 per cent) of the available surface water can be utilized because:
  • Over 90% of annual flow of the Himalayan rivers occur over a four-month period.
  • Potential to capture such resources is complicated and limited by suitable storage reservoir sites.

 Extent of Pollution:

The most significant stretches of pollution highlighted by the CPCB assessment include:

  • The Mithi river from Powai to Dharavi with a BOD (Biochemical Oxygen Demand) of 250 mg/l.
  • The Godavari — from Someshwar to Rahed — with a BOD of 5.0-80 mg/l.
  • The Sabarmati — Kheroj to Vautha — with a BOD from 4.0-147 mg/l and
  • The Hindon — Saharanpur to Ghaziabad — with a BOD of 48-120 mg/l.

Reasons behind the river being more polluted:

  • Rapid urbanisation is widening the gap, since infrastructure planning is not keeping pace with growth in housing.
  • There is poor infrastructure available in a large number of cities and towns located near rivers.
  • Managing sewage requires steady funding of treatment plants for all urban agglomerations that discharge their waste into rivers, and also a reliable power supply.
  • There is failure of several national programs run by the Centre for river conservation, wetland preservation and water quality monitoring.
  • The sewage and industrial effluents freely flow into the rivers in several cities.
  • Deficit between the sewage available and the volume generated along the polluted stretches is estimated at 13,196 million liters a day.
  • Low priority is accorded to the enforcement of laws by SPCBs and pollution control committees.

Ground Water Resources

  • The total replenishable groundwater resources in the country are about 432 cubic km.
  • Ganga and the Brahmaputra basins, have about 46 per cent of the total replenishable groundwater resources.
  • The level of groundwater utilization is relatively high in the river basins lying in north-western region and parts of south India.
  • The groundwater utilisation is very high in the states of Punjab, Haryana, Rajasthan, and Tamil Nadu.
  • However, there are States like Chhattisgarh, Odisha, Kerala, etc., which utilize only small proportion of their groundwater potentials.
  • India also relies excessively on groundwater resources, which accounts for over 50% of irrigated area with 20 million tube wells installed.
  • India has built nearly 5,000 major or medium dams, barrages, etc. to store the river waters and enhance ground water recharging.

Importance of Groundwater

  • Groundwater supports the livelihoods of over 26 crore farmers and agricultural labourers.
  • Groundwater is one of the most important water sources in India accounting for 63% of all irrigation water and over 80% of rural and urban domestic water supplies.
  • Wells, including dug wells, shallow tube-wells and deep tube wells provide about 61.6% of water for irrigation, followed by canals with 24.5%.


The groundwater crisis is embedded at two different levels:

  • Groundwater exploitation of aquifers (where groundwater is stored) in different parts of the India and
  • Groundwater contamination that find origins, both in geogenic source such as Arsenic and Fluoride along with anthropogenic sources of contamination primarily due to poor disposal of waste and wastewater.

Groundwater is the water that seeps through rocks and soil and is stored below the ground. The rocks in which groundwater is stored are called aquifers. Aquifers are typically made up of gravel, sand, sandstone or limestone.


  • The United Nations Educational, Scientific and Cultural Organization (UNESCO) World Water Development Report states that India is the largest extractor of groundwater in the world.
  • Two-thirds of the total amount is abstracted in Asia with India, China, Pakistan, Iran and Bangladesh as major consumers.
  • 21 major cities of India are expected to run out of groundwater as soon as 2020, affecting around 100 million people, the think tank’s new report states.
  • About 75% of households do not have drinking water at home, 84% rural households do not have piped water access, and 70% of India’s water is contaminated, with the country currently ranked 120 among 122 in the water quality index.
  • By 2030, the country’s water demand is projected to be twice the available supply, implying severe water scarcity for hundreds of millions and an eventual loss of around 6% of the country’s GDP.

Reasons for Depletion

  • Increased demand for water for domestic, industrial and agricultural needs and limited surface water resources lead to the over-exploitation of groundwater resources.
  • There are limited storage facilities owing to the hard rock terrain, along with the added disadvantage of lack of rainfall, especially in central Indian states.
  • Green Revolution enabled water intensive crops to be grown in drought prone/ water deficit regions, leading to over extraction of groundwater.
  • Frequent pumping of water from the ground without waiting for its replenishment leads to quick depletion.
  • Subsidies on electricity and high MSP for water intensive crops is also leading reasons for depletion.
  • Water contamination as in the case of pollution by landfills, septic tanks, leaky underground gas tanks, and from overuse of fertilizers and pesticides lead to damage and depletion of groundwater resources.
  • Inadequate regulation of groundwater laws encourages the exhaustion of groundwater resources without any penalty.
  • Deforestation, unscientific methods of agriculture, chemical effluents from industries, lack of sanitation also lead to pollution of groundwater, making it unusable.


  • India ranks 120 among 122 countries in the water quality index, an astounding 2,00,000 people die each year due to polluted water.
  • Droughts are becoming more frequent, creating severe problems,


  • There should be restrictions to cut off the access to groundwater in areas identified as “critical” and “dark zones”, where the water table is overused or very low.
  • There is a need to treat water as common resource rather than private property to prevent its overexploitation
  • Problems and issues such as water logging, salinity, agricultural toxins, and industrial effluents, all need to be properly looked into.
  • Research and scientific evaluations should be done before forming any policy.
  • Water depletion can be controlled by reducing electricity subsidies.
  • Another way of efficiently using groundwater is by encouraging farmers to adopt micro-irrigation techniques such as drip irrigation and micro-sprinklers. Government has initiated schemes like DRIP programme, more drop per crop, Krishi Sinchai Yojana to ensure economical water use practices in agriculture.
  • Bottom-up approach by empowering the local community to become active participants in managing groundwater.
  • Creating regulatory options at the community level such as panchayat is also one among the feasible solutions.
  • Traditional methods of water conservation should be encouraged to minimize the depletion of water resources.
  • Technology should be used extensively for determining the relationship between surface hydrological units and hydrological units below the ground, identification of groundwater recharge areas, mapping of groundwater etc.
  • Artificial recharge of tube wells, water reuse, afforestation, scientific methods of agriculture should also be done.
  • Imparting key hydrogeological skills to nonprofits and rural practitioners to improve decentralised water management in India.

Ground Water Extraction Rules

  • India is the largest user of groundwater in the world which is about 25% of the global groundwater extraction.
  • 90% of the annual ground water extraction is primarily for agricultural activities.
  • 10% of the extraction is for drinking and domestic as well as industrial uses.
  • Industrial use is estimated to account for only 5% of the annual ground water extraction in the country.
  • Central Ground Water Authority was constituted under the Environment Protection Act, 1986 in 1997.


Water scarcity and Associated issues

Water scarcity is the lack of freshwater resources to satisfy water demand. It is manifested by partial or no satisfaction of expressed demand, economic competition for water quantity or quality, disputes between users, irreversible groundwater depletion, and negative effects on the environment.

  • One-third of the global population (2 billion people) live under situations of severe water scarcity at least one month of the year.


Water Crisis in India 

  • Water crisis is the difficulty of obtaining sources of fresh water for use due to depletion and deterioration of available water resources.
  • Water shortages may be caused by climate change, such as altered weather patterns including droughts or floods, increased pollution, and increased human demand and overuse of water.

In addition, water scarcity in India is expected to worsen as the overall population is expected to increase to 1.6 billion by the year 2050.

 The NITI Aayog released the results of a study warning that India is facing its ‘worst’ water crisis in history and that demand for potable water will outstrip supply by 2030 if steps are not taken.

Nearly 163 million of India’s population of 1.3 billion lack access to clean water close to home, the most of any country, according to a 2018 report by Britain-based charity WaterAid.

Nearly 600 million Indians faced high to extreme water stress and about 2,00,000 people died every year due to inadequate access to safe water. Twenty-one cities, including Delhi, Bengaluru, Chennai and Hyderabad will run out of groundwater by 2020, affecting 100 million people, the study noted. If matters are to continue, there will be a 6% loss in the country’s Gross Domestic Product (GDP) by 2050.


Alarming facts about Water Stress:

 More than 163 million Indians – higher than the population of Russia – do not have access to safe drinking water.

Irrespective of the source of water, in most parts of rural India, availability of water decreases dramatically in the summer months as the water levels drop and surface sources may dry up.

India’s estimated per capita availability of water in 2025 will be 1,341 cubic metre. This may further fall to 1,140 cubic metre in 2050, bringing it closer to becoming water-scarce.

NITI Aayog’s Composite Water Management Index, India ranks 120 out of 122 countries.

India is ranked 13th among the 17 most water-stressed countries of the world.

According to the Ministry of Urban Development, 80% of India’s surface water is polluted.

Sustainable Development Goal target 6.1 calls for universal and equitable access to safe and affordable drinking water. The target is tracked with the indicator of “safely managed drinking water services” – drinking water from an improved water source that is located on premises, available when needed, and free from faecal and priority chemical contamination.


Causes for Water Pollution and Water  stress in India

  • Population growth leads to high water demand both by households and agriculture.
  • Large agricultural sector accounts for most of the water use in India leaving less resources for industry and households.
  • Rapid urbanization: High water demand by the dense population living in cities in India is causing stress on groundwater and surface water resources.
  • Climate change: Climate change will have significant impacts on water resources in Himalayas and monsoonal rainfall.
  • Rising temperatures will increase evaporation and lead to increases in precipitation, though there will be more stark regional variations in rainfall.
  • Both droughts and floods may become more frequent in different regions at different times, and dramatic changes in snowfall and snow melt are expected in mountainous areas.
  • Depletion of aquifers: Due to the expanding human population, many of the world’s major aquifers are becoming depleted. due both for direct human consumption as well as agricultural irrigation by groundwater.
  • Pollution and water protection: Many pollutants threaten water supplies, but the most widespread, especially in developing countries, is the discharge of raw municipal sewage, untreated industrial waste and agricultural runoff carrying pesticides, insecticides and fertilizers into natural waters.
  • Although India has made improvements over the past decades to both the availability and quality of municipal drinking water systems, its large population has stressed planned water resources and rural areas are left out.


Consequences of Water Crisis and Pollution

  • Increased International Conflict: Indian freshwater resources in Himalayas are crucial for Pakistan, Afghanistan, Tibet, Bangladesh, Nepal, Myanmar etc. as well. Prolonged water stress may lead to international conflicts.
  • Lack of Access to Clean Water: Only 33% of the country has access to traditional sanitation. Without access to clean freshwater, these vulnerable populations are exposed to deadly water-borne illnesses and water gathering can limit educational and economic opportunities
  • Food Shortages: With a global population on pace to reach 6 billion by 2050, shrinking water resources will make it difficult for food production to keep up with rising demand. The United Nations warns that political turmoil, social unrest, civil war and terrorism could result from food shortages unless food production is increased by 60% by 2050. Agriculture already accounts for about 70% of global freshwater withdrawals to keep up with current food demand
  • Energy Shortages: World energy requirements are rapidly increasing with modernization and population growth; however, energy production is one of the world’s greatest consumers of freshwater resources. In the United States, thermoelectric power plants accounted for 38% of freshwater withdrawals in 2010. Global electricity demand is projected to grow 70% by the year 2035 with India and China accounting for half of the growth.
  • Economic Slowdown: The United Nations estimates that half of the world’s population will live in areas of high-water stress by the year 2030. It is difficult to have a thriving economy when fresh water is not easily accessible for industrial, farming, and individual use. Production of water-intensive goods like cars, food, and clothing could be limited by lack of freshwater resources.
  • In addition, rapid growth in India’s urban areas has stretched government solutions, which have been compromised by over- privatization leading to exclusion of urban poor from formal water supply.


Solutions To Water Crisis

  • Put a realistic price on water: We charge so little for it, yet it costs so much to manage, that there’s little motivation to address the pressing needs of the aging water infrastructure.
  • Educate to change consumption and lifestyles: In the end, changing the face of this crisis involves education to motivate new behaviours. Coping with the coming era of water scarcity will require major overhaul of all forms of consumption.
  • Invent new water conservation technologies: In areas where aquifers are drying up and rainwater is increasingly unpredictable, innovation is needed.
  • Recycle waste water
  • Solar-powered water purifiers: Hot climates suffer from water shortage the most. Deepika Kurup invented a way to use zinc oxide and titanium dioxide in containers that expose it to ultraviolet radiation and cleanse the water, making it suitable to drink.
  • Improve irrigation and agricultural practices: Some 70 percent of the world’s freshwater is used for agriculture like drip irrigation, sprinkle irrigation, less extraction of ground water.
  • Develop energy efficient desalination plants: To date, desalination has been an energy- intensive solution to water scarcity. Typically, the Middle East has capitalized on its large energy reserves to build desalination plants. But Saudi Arabia could be fostering a new kind of desalination with its recent announcement to use solar-powered plants.
  • Improve water catchment and harvesting: Rainwater harvesting is a method to capture and store rainwater for various uses. It is also used to recharge groundwater aquifers. It is a low cost and eco-friendly technique for preserving water by guiding the rain water to borewell, pits and wells:
    • Rainwater harvesting increases water availability,
    • Checks the declining groundwater table,
    • Improves the quality of groundwater through dilution of contaminants, like fluoride and nitrates,
    • Prevents soil erosion, and flooding and
    • Arrests salt water intrusion in coastal areas if used to recharge aquifers.
  • Look to community-based governance and partnerships: Community organizations elevate the experiences of those whose voices merit more influence.
  • Improve distribution infrastructure: Poor infrastructure is devastating to health and the economy. It wastes resources, adds costs, diminishes the quality of life, and allows preventable water-borne diseases to spread among vulnerable populations.
  • Address pollution: Measuring and monitoring water quality is essential to human health and biodiversity.
  • R&D / Innovation: Access to water in a water- scarce world will become a much higher priority in business decisions. Communities are likely to pursue public-private partnerships that draw on the innovative capacities of companies. One example— cities that operate sewage treatment plants are likely to pursue partnerships with clean energy producers to fertilize algae and other biofuel crops with wastewater.


Measures taken by Government to de-stress Water Crisis:

  • Ministry of Jal Shakti launched ‘Jal Shakti Abhiyan’– campaign for water conservation and water security. The campaign run through citizen participation while focus on water-stressed districts and blocks in the country.

 Jal Shakti Ministry launches framework for water quality  testing,      monitoring.

Key facts:

  • The framework is part of the Centre’s flagship Jal Jeevan Mission. Of the ₹3.6 lakh crore Jal Jeevan budget, 2% has been earmarked for quality monitoring.
  • The guidelines mandate a network of the National Accreditation Board for Testing and Calibration Laboratories (NABL) accredited labs to be set up in every State, district and block over the next year.
  • At the panchayat level, teams of women in the village water and sanitation committees will be given field testing kits.
  • State governments can include private players as part of the network, but the Centre has capped tariffs to ensure that they remain within the reach of the common man.
  • Apart from voluntary tests by members of the public, officials have been mandated to do regular inspections. All results of testing will be fed into the Water Quality Information Management System.

The basic water quality parameters prescribed under the guidelines are:

pH value, total dissolved solids, turbidity, chloride, total alkalinity, total hardness, sulphate, iron, total arsenic, fluoride, nitrate, total coliform bacteria, e.coil or thermo-tolerant coliform bacteria.

  • Pradhan Mantri Krishi Sinchay Yojana (PMKSY) – ‘Har khet ko pani’ and ‘More Crop per Drop’ – focuses on improving water use efficiency.
  • Other measures such as National Water Mission, National Mission for Clean Ganga, Dam Improvement and Rehabilitation Programme, Ground water management, Flood control and Forecast, Biodiversity Conservation, Wetland conservation, Green India Mission, CAMPA, etc.
  • Jal Kranti Abhiyan: The government is making active efforts to revolutionize villages and cities through block-level water conservation schemes. It aims at turning one water scarce village in each district of the country into water surplus water village through a holistic and integrated approach by adopting conservation and management techniques.
  • National Water Mission:
    • The Government of India has launched the National Water Mission with the objective of conservation of water, minimizing wastage and ensuring more equitable distribution both across and within states through integrated water resources development and management.
    • One of the objectives of the Mission is to increase the water use efficiency by 20%.
  • The new ‘Jal Shakti’ Ministry is formed by merging erstwhile two ministries, namely:
    • Ministry of Water Resources, River Development and Ganga Rejuvenation
    • Ministry of Drinking Water and Sanitation
  • Atal Bhujal Yojana – Aims to promote sustainable ground water management with community participation in select over-exploited and water stressed areas.
  • Restructured Natioanal Rural Drinking Water Programme – Improving coverage of piped drinking water in rural areas. Increase level of service delivery. Thrust on coverage of water quality affected habitations.
  • Envisioned as an annual exercise, the Composite Water Management Index (CWMI), to evaluate States, has been developed by the NITI Aayog and comprises 9 broad sectors with 28 different indicators covering various aspects of groundwater, restoration of water bodies, irrigation, farm practices, drinking water, policy and governance.
  • Improper attention given to management of watersheds in the country. The scientific way of managing water from watershed is well tested for positive results. Silting of wetlands is also a problem, with periodic silting and degradation the water retention capacity reduces significantly and adds to the crisis.
  • Another important issue that needs to be addressed, particularly in urban areas, is the leakage of pipes providing water. We cannot allow this to continue any longer. Putting in place an efficient piped supply system has to be top on the agenda of policymakers and planners.
  • Reviving ancient systems of water harvesting techniques:
  • Micro irrigation practices like drip and sprinkler systems have to be promoted in a big way for efficient use of water for agriculture. Both in urban and rural areas, digging of rainwater harvesting pits must be made mandatory for all types of buildings.


Water Governance


  • Water Governance poses one of the biggest challenges in modern-day India that looks out for definitive solutions.
  • How this scare water resource is to be allocated? How to generate livelihood in the food-energy nexus? How to keep the order of the biosphere balanced.


Need for Water Management in India

  • Water is a cyclic resource with abundant supplies on the globe. Approximately, 71 per cent of the earth’s surface is covered with it but freshwater constitutes only about 3 per cent of the total water.
  • India accounts for about 2.45 per cent of the world’s surface area, 4 per cent of the world’s water resources and about 16 per cent of the world’s population.
  • The total water available from precipitation in the country in a year is about 4,000 cubic km.
  • India experiences an average precipitation of 1170 mm per year.
  • The availability from surface water and replenishable groundwater is 1,869 cubic km.
  • Out of this only 60 per cent can be put to beneficial uses.
  • Thus, the total utilizable water resource in the country is only 1,122 cubic km.

Key aspects of water governance:

-The key aspects of an effective system of water governance in a water blessed country which includes a comprehensive policy followed by an Action Plan to formulate the policy.

-Need to emphasized on the importance of resource literacy on water and building institutions in line with framed policies.

-Experts prescribed the top-down approach and definition of ‘per capita availability’ to be rechecked and substituted with a bottom-up approach and relevant definitions, that is, a more localized treatment of governing water.


Some lacunas present in the state of water governance that needs to be addressed:

Problem /Challenges in Water governance

  • Information – The lack of credible water information.
  • Multiple institutions
  • Unsustainable extraction
  • Absence of National Policy
  • Water infrastructure perform far below its optimum
  • Soil moisture – Soil moisture represents another major challenge
  • Increasing water footprint

Lack of reliable information and doctored data which is unfortunately aided by the conflict of interest among governing bodies like the Central Water Commission (CWC), Ministry of Water Resources (MoWR), the regulators, the financial agencies.


  • Suggestion is to bring transparency and bridge the information gap, by putting data into public domain right away.
  • Localised storage options, flood management, optimal use of reservoirs, river management – its flow, pollution and biodiversity, catchment management via enhancing water recharge, studying the flow of sediments.
  • Management of agriculture – regulation of water-intensive crops and cropping pattern, regulations for groundwater consumption.
  • An Urban Water Policy focusing on Water Smart cities, corruption-free quality and pollution management and a check on climate change induced by anthropogenic activities that causes harm to water resources are some of the governance tools to sought-after.

Water Governance implementation challenges in the main themes:

These governance challenges can affect the implementation of the SDG water-related targets to a lesser or greater degree depending on the water management function.

For example :

Drinking water and sanitation (targets 6.1 and 6.2):

  • The lack of capacity, in particular at sub-national levels, represent an important obstacle to meeting current and future demands.
  • The World population will grow to around 9 billion by 2050, with rapidly increasing proportion living in urban areas.
  • These socio-economic and demographic trends raise important challenges for countries and cities to mobilise the infrastructure, expertise and competent staff necessary to ensure the provision of safe drinking water and sanitation.
  • Knowledge and know-how may also be needed to develop innovative approaches (be it technical or non-technical) to water service provision in light of growing demands.
  • In addition, insufficient or inadequate funding can also be an important challenge: countries will be expected to mobilise substantial financial resources to build and maintain new networks, replace and modernise existing water infrastructures and ensure the performance of service provision.

Water resources management (targets 6.4 and 6.5):

  • The management of water resources is an issue particularly sensitive to the question of scale.
  • The mismatch between administrative limits and hydrological boundaries can lead to local actors (e.g. municipalities) placing their own interests ahead when designing and implementing water resources management policies and strategies, rather than integrating the needs of the river basin and aquifers.
  • Managing water resources efficiently can also be hindered by diverging interests between urban and rural areas for example, or between up-stream and downstream regions.
  • This can hinder the water-use efficiency across sectors and prevent the adoption of convergent objectives for sustainable withdrawals and supply of freshwater to address water scarcity.

Water quality and wastewater treatment (target 6.3).

  • Ensuring good quality level for water requires collective and co-ordinated actions across actors and sectors. It is as such particularly sensitive to sectoral fragmentation, which can hinder collective efforts to reducing pollution.
  • Eliminating dumping, minimizing release of hazardous chemicals and materials, halving the proportion of untreated wastewater, and increasing recycling and safe reuse.
  • Meeting water quality targets can also be hampered by limited enforcement.
  • A lack of accountability and transparency in complying with existing standards for quality and wastewater treatment, in particular when governments do not have the capacity to monitor their performance and civil society is not fully engaged to hold them accountable.

Risk management related to disasters and climate change (target 6.6).

  • Inadequate information production and sharing for what concerns meteorological and hydrological data is an important obstacle to managing the risks related to extreme event and global warming.
  • Often, countries deal with data scattered across various sources (scientific, institutional, etc.) which hamper a common understanding of the risks and exposure to natural disasters such as droughts and floods.
  • It results in the absence of common frame of reference regarding safety measures and levels of risks and different levels of knowledge and awareness across actors.

Articulating the best practices of water governance:

  • An example of a World Bank project in Andhra Pradesh where they educated and equipped the local community to understand their water budget and how the water levels have been changing, and what should be the appropriate cropping patterns.
  • A ‘River Parliament’ in a village in India wherein the locals came to meet once a while to discuss water management.
  • Durgashakti Nagpal’s (IAS) view and experience as a civil servant on water governance highlights the communities affected by water insecurity and are at the frontlines of vulnerability.
  • Pointing out the problem in citizen participation, they maintains that due to the non-realization of the urban dwellers that water management is their problem and view that they are not part of the governance, they don’t get actively involved in water governance.
  • There is a need for a ward level committee to educate the citizens about the source of water, the importance of conservation, and how they can play a role in the management and, subsequently, governance.
  • The demand for a more significant role of citizens is something that should not be ever negated.
  • While emphasizing dams and the ‘development’ role, experts criticized that the 5000 dams were being constructed across India without civil consent and opinion, which has only done more harm than good, especially to the vulnerable groups.
  • There is a need for post facto assessment; the capacity to learn lessons and change accordingly is also what the governing institutions should bring about as a character.
  • An example of how NDMA should have an ‘independent credible assessment’ as to what happened and who should be accountable of and the shortcomings that made the disaster turn into a calamity.
  • Further, highlighted that official buildings should first equip themselves with a rain harvesting system before making it mandatory for private institutions and facilities.

On the untreated sewage, advocated for the formulation of a decentralized system of sewage management in the urban localities and a transparent committee that will monitor and evaluate the progress.


 National water policy

National Water policy was formulated to govern the planning and development of water resources and their optimum utilization. The first National Water Policy was adopted in 1987, it was reviewed and updated in 2002 and later in 2012.

  • Government plans to come out with an updated version of National Water Policy with key changes in governance structures and regulatory framework.
  • Plans are also to set up a National Bureau of Water Use Efficiency. Building consensus among the states within the constitutional framework is the pre-condition for making this changes.

Salient features

The major provisions under the policy are:

  1. Envisages to establish a standardized national information system with a network of data banks and data bases .
  2. Resource planning and recycling for providing maximum availability.
  3. To give importance to the impact of projects on human settlements and environment.
  4. Guidelines for the safety of storage dams and other water-related structures.
  5. Regulate exploitation of groundwater .
  6. Setting water allocation priorities in the following order: Drinking water, Irrigation, Hydropower, Navigation, Industrial and other uses.
  7. The water rates for surface water and ground water should be rationalized with due regard to the interests of small and marginal farmers.

The policy also deals with participation of farmers and voluntary agencies, water quality, water zoning, conservation of water, flood and drought management, erosion etc


National Water Policy 2012:

The salient features of national water policy (2012) are as follows:

  • Emphasis on the need for a national water framework law, comprehensive legislation for optimum development of inter-State rivers and river valleys.
  • Water, after meeting the pre-emptive needs for safe drinking water and sanitation, achieving food security, supporting poor people dependent on agriculture for their livelihood and high priority allocation for minimum eco-system needs, be treated as economic good so as to promote its conservation and efficient use.
  • Ecological needs of the river should be determined recognizing that river flows are characterized by low or no flows, small floods (freshets), large floods and flow variability and should accommodate development needs. A portion of river flows should be kept aside to meet ecological needs ensuring that the proportional low and high flow releases correspond in time closely to the natural flow regime.
  • Adaptation strategies in view of climate change for designing and management of water resources structures and review of acceptability criteria has been emphasized.
  • A system to evolve benchmarks for water uses for different purposes, i.e., water footprints, and water auditing be developed to ensure efficient use of water. Project financing has been suggested as a tool to incentivize efficient & economic use of water.
  • Setting up of Water Regulatory Authority has been recommended.
  • Incentivization of recycle and re-use has been recommended.
  • Water Users Associations should be given statutory powers to collect and retain a portion of water charges, manage the volumetric quantum of water allotted to them and maintain the distribution system in their jurisdiction.
  • Removal of large disparity in stipulations for water supply in urban areas and in rural areas has been recommended.
  • Water resources projects and services should be managed with community participation. Wherever the State Governments or local governing bodies so decide, the private sector can be encouraged to become a service provider in public private partnership model to meet agreed terms of service delivery, including penalties for failure.
  • Adequate grants to the States to update technology, design practices, planning and management practices, preparation of annual water balances and accounts for the site and basin, preparation of hydrologic balances for water systems, and benchmarking and performance evaluation etc.
  • Minimum Water Flow: To maintain the minimum flow of a portion of a river to meet ecological needs.
    • In 2018, such an approach led the government to require minimum water levels to be maintained in the Ganga throughout the year by refraining from hoarding water beyond a point.
    • Emphasis was also made to make a minimum quantity of potable water available to citizens for maintaining essential health and hygiene.
  • Inter-basin Transfers: To meet basic human needs and achieve equity and social justice, inter-basin transfers of water need to be considered on the basis of the merits of each case after evaluating the environmental, economic and social impacts of such transfers.

Why is there a need of updated National Water Policy?

  • There are lots of changes that are required in the policy.
  • Privatization of water usage should be defined.
  • Agriculture was there but not included in the policy parameters.
  • River revitalization is required to be revised.
  • Technological innovation is required with the sensors, GIS and satellite imagery.
  • Need to modulate the water by having a good picture of its path and quantity.
  • Need to go back from basin to sub-basin to watershed and down into village water budgeting level.
  • Policy does not deter use among those who can afford to pay for water.
  • Policy does not follow polluter pay principle, rather it gives incentives for effluent treatment.
  • Policy is criticized for terming water as an economic good.
  • It does not focus on water pollution
  • India’s water table is falling in most parts; there is fluoride, arsenic, mercury, even uranium in our groundwater.
  • The groundwater and sand extraction from most river beds and basins has turned unsustainable.
  • Water is being diverted from food-crops to cash-crops; livelihoods to lifestyles; rural to urban— mismanagement is a bigger reason for the drought.
  • Water shortages are hurting India’s ability to produce power and 40% thermal power plants are in areas facing high water stress, a recent World Resources Institute report says.


Paradigm shift in approach from service provider of water to facilitator of service.

  • Policy does not deter use among those who can afford to pay for water.
  • PPP mode may not ensure equity.
  • Policy does not follow polluter pay principle, rather it gives incentives for effluent treatment.
  • Policy was criticized for terming Water as an economic good.
  • In some regions it has not yet become successful .
  • The policy does not focus on the reduction of water pollution.
  • The policy doesn’t lay out objective for commercial use of water, especially ground water

Way Forward:

  • Hydrological boundaries, rather than administrative or political boundaries, should be part of the water governance structure in the country
  • Building consensus among the States within the Constitutional framework is a pre-condition for making the changes.
  • Water conservation, along with water harvesting and judicious and multiple use of water, are key to tackling the water challenges that India faces.
  • Rejuvenation and revitalisation of traditional water bodies and resources through the age-old conservation methods.
  • Need for disseminating modern water technologies in an extensive fashion.
  • Relook basin and sub-basin planning
  • Water policy should take in all recommendations and warning given by NITI Aayog
  • Batting for policy changes for giving incentive to crops using less water.
  • Participatory groundwater management should be promoted in a big way to maintain quality and sustainability.


Interlinking of Rivers Project

The National River Linking Project (NRLP) formally known as the National Perspective Plan, envisages the transfer of water from water ‘surplus’ basins where there is flooding to water ‘deficit’ basins where there is drought/scarcity, through inter-basin water transfer projects.

Digging further into the term ‘surplus’ as per the Government, states that it is the extra water available in a river after it meets the humans’ requirement of irrigation, domestic consumption and industries thereby underestimating the need of the water for the river itself. The term ‘deficit’ has also been viewed in terms of humans only and not from the river’s perspective, which includes many other factors.

National River Linking Project (NRLP)

This project envisages the transfer of water from the water-excess basin to the water-deficient basin by interlinking 37 rivers of India by a network of almost 3000 storage dams. This will form a gigantic South Asian water grid.

There are two components to this project:

  1. Himalayan Component
  2. Peninsular Component

Scope of the Project

The National River Interlinking Project will comprise of 30 links to connect 37 rivers across the nation through a network of nearly 3000 storage dams to form a gigantic South Asian Water Grid. It includes two components:

Projects in the Himalayan component (Source: National Water Development Agency)

  • Himalayan Rivers Development Component under which 14 links have been identified. This component aims to construct storage reservoirs on the Ganga and Brahmaputra rivers, as well as their tributaries in India and Nepal. The aim is to conserve monsoon flows for irrigation and hydropower generation, along with flood control. The linkage will transfer surplus flows of the Kosi, Gandak and Ghagra to the west. A link between the Ganga and Yamuna is also proposed to transfer the surplus water to drought-prone areas of Haryana, Rajasthan and Gujarat.


Himalayan component

Map of the Ganges (orange), Brahmaputra (violet), and Meghna (green) drainage basins.

Himalayan Rivers Development envisages construction of storage reservoirs on the main Ganga and the Brahmaputra and their principal tributaries in India and Nepal along with inter-linking canal system to transfer surplus flows of the eastern tributaries of the Ganga to the West apart from linking of the main Brahmaputra with the Ganga.

Apart from providing irrigation to an additional area of about 22 million hectares and generating about 30 million kilowatt of hydro-power, it will provide substantial flood control in the Ganga-Brahmaputra basin. The Scheme will benefit not only the States in the Ganga-Brahmaputra Basin, but also Nepal and Bangladesh, assuming river flow management treaties are successfully negotiated.

 Peninsular Component

This Scheme is divided in four major parts.

  1. Interlinking of Mahanadi-Godavari-Krishna-Palar-Pennar-Kaveri,
  2. Interlinking of West Flowing Rivers, North of Mumbai and South of Tapi,
  3. Inter-linking of Ken with Chambal and
  4. Diversion of some water from West Flowing Rivers

This component will irrigate an additional 25 million hectares by surface waters, 10 million hectares by increased use of ground waters and generate hydro power, apart from benefits of improved flood control and regional navigation.

Proponents of the project argue that/ BENEFITS of Interlinking of rivers

  • It will irrigate about 87 million acres of farmland, control floods, and generate 34 GW of hydroelectric power.
  • This will cut farmers’ dependence on monsoon rains by bringing millions of hectares of cultivatable land under irrigation.
  • Crop productivity would increase and so would revenues for the State.  Even one bad monsoon has a direct and debilitating economic impact.
  • The river linking project will ease the water shortages in western and southern India while mitigating the impacts of recurrent floods in eastern India.
  • Simultaneous floods and droughts continue to wreak havoc, destroying the lives and livelihoods of millions.
  • India needs clean energy to fuel its development processes, and river water can be leveraged for this.
  • Fulfilling water needs impact socio-economic life of people which will help end poverty. Need for interlinking of rivers to prevent inter-state water disputes.  Potential benefits to transportation through navigation, as well as broadening income sources in rural areas through fishing.
  • Judicious Use of Water Resources
  • Address the issue of Water Stress
  • Can improve the irrigation coverage
  • Power generation
  • Disaster Management


Critics argue that/ Issues and Concerns about interlinking of Rivers

  • Interlinking of rivers is a very expensive proposal.
  • The river interlinking project will adversely affect land, forests, biodiversity, rivers and the livelihood of millions of people
  • The Ken-Betwa link threatens about 200 sq. km of the Panna tiger reserve Interlinking of rivers will lead to destruction of forests, wetlands and local water bodies, which are major groundwater recharge mechanisms.
  • Less than positive experience that other countries have, like diversion of Amu Darya and the Syr Darya or the Australia’s experiments in its Murray Darling basin.
  • It causes massive displacement of people. Huge burden on the government to deal with the issue of rehabilitation of displaced people.
  • Due to interlinking of rivers, there will be decrease in the amount of fresh water entering seas and this will cause a serious threat to the marine life
  • The Shah committee pointed out that the linking of rivers will affect natural supply of nutrients for agricultural lands through curtailing flooding of downstream areas.
  • Artificial change of course
  • Bypass the crucial dryland areas
  • Impact on Environment
  • Impact on rivers
  • he concerns about sediment management, especially on the Himalayan system loom large. When the idea is to transfer water from the ‘surplus’ Himalayan river systems to ‘deficit’ basins of the southern part of India, the differential sediment regime defining the flow regimes need to be plugged into the equation. This will entail changes in ecosystem structures in both parts.
  • Damming India’s east-coast rivers to take their water westwards will curtail downstream flooding and thereby, the supply of sediment—a natural nutrient—destroying fragile coastal ecosystems and causing coastal and delta erosion
  • Federal contentions


  • India has 18 percent of the world’s population but only 4 percent of the usable water resources Irrigation potential from interlinking rivers will have limited impact.
  • The net national irrigated area from big dams has decreased and India’s irrigated area has gone up primarily due to groundwater.
  • Large hydropower projects are no longer a viable option in India.  Storing large quantities of waters. Most of the sites suitable for the big reservoirs are in Nepal, Bhutan and in the North-East—who are in opposition to big storage reservoirs.
  • There are political challenges as well. Water transfer and water sharing are sensitive subjects. If the glaciers don’t sustain their glacier mass due to climate change, the interlinking project will have limited benefit.
  • Usually rivers change their course and direction in about 100 years and if this happens after interlinking, then the project will not be feasible for a longer run.




  • The project aims to transfer surplus water from the Ken river in MP to Betwa in UP to irrigate the drought-prone Bundelkhand region spread across the districts of two states mainly Jhansi, Banda, Lalitpur and Mahoba districts of UP and Tikamgarh, Panna and Chhatarpur districts of MP.

Benefits of interlinking:

  • Enhances water and food security.
  • Proper utilisation of water.
  • Boost to agriculture.
  • Disaster mitigation.
  • Boost to transportation.

An Environmental Hazard

Ken-Betwa river link entails a 231-kilometre (144 mile) canal between the two rivers in the states of Madhya Pradesh and Uttar Pradesh, along with two dams and reservoirs; the felling of more than 1.8 million trees; and the usage of 6,017 hectares (23 sq miles) of forest land, including the Panna Tiger Reserve, with special mention of endangered wildlife species that will be impacted. The project is also expected to consume nearly 6,000 hectares of non-forest land, with approximately 5,000 homes being submerged as per the National Water Development Authority feasibility report.


The IRL project is a great challenge and an opportunity to address the water issues arising out of climate change. The long-term solution to water scarcity lies in making the IRL project work by building a network of dams and canals across the length and breadth of the country. However, interlinking has to take place after a detailed study so that does not cause any problem to the environment or aquatic life.




1. “River linking projects for the country are a great challenge and at the same time an opportunity to address the water issues arising out of climate change.” Critically analyse the statement in the light of recent floods witnessed across the country.(250 words)


2) Do you think the interlinking of river in India is a sustainable water management practice? Analyse with suitable examples. (250 words)



3) Account for the ecological concerns around river-linking projects in India and suggest solutions to address the same. (250 words)


4) Interlinking of rivers may address the issue of paucity of water but poses a serious threat to the indigenous ecological diversity of the said rivers. Comment. (200 Words)



The oceans cover over 70% of the globe. Its health, wellbeing of humanity and the living environment that sustains us all are inextricably linked.

Yet neglect of ocean acidification, climate change, polluting activities and over-exploitation of marine resources have made oceans, one of the earth’s most threatened ecosystems.

Marine pollution, also known as ocean pollution, is the spreading of harmful substances such as oil, plastic, industrial and agricultural waste and chemical particles into the ocean.

Causes of Ocean Pollution

There are various ways in which pollution enters the ocean:

  • Sewage: Sewage or polluting substances flow through sewage, rivers, or drainages directly into the ocean.
  • Toxic Chemicals From Industries: Industrial waste which is directly discharged into the oceans, results in ocean pollution.
    • The hazardous and toxic chemicals affect marine life.
    • Also, they raise the temperature of the ocean and cause thermal pollution. Aquatic animals and plants have difficulty surviving at higher temperatures.
  • Land Runoff: Land-based sources (such as agricultural run-off, discharge of nutrients and pesticides and untreated sewage including plastics) account for approximately 80% of marine pollution. The runoff picks up man-made, harmful contaminants that pollute the ocean, including fertilizers, petroleum, pesticides and other forms of soil contaminants.
  • Large Scale Oil Spills: Pollution caused by ships is a huge source of ocean pollution, the most devastating effect of which is oil spills.
    • Crude oil lasts for years in the sea and is extremely toxic to marine life, it suffocates the marine animals to death.
    • Crude oil is also extremely difficult to clean up.
  • Ocean Mining: Ocean mining sites drilling for silver, gold, copper, cobalt, and zinc create sulfide deposits up to three and a half thousand meters down into the ocean.
  • Plastic Pollution: In 2006, the United Nations Environment Programme estimated that every square mile of ocean contains 46,000 pieces of floating plastic.
    • Once discarded, plastics are weathered and eroded into very small fragments known as microplastics. These together with plastic pellets are already found in most beaches around the world.
    • Plastic materials and other litter can become concentrated in certain areas called gyres as a result of marine pollution gathered by oceanic currents. For example, the North Pacific Gyre is now referred to as the Great Pacific Garbage Patch, where waste material from across the North Pacific Ocean, including coastal waters off North America and Japan, are drawn together.
  • In addition to all these factors, the oceans are highly affected by carbon dioxide and climate changes, which impacts primarily the ecosystems and fish communities that live in the ocean. In particular, the rising levels of CO2 leads to ocean acidification.
  • Other factors like coastal tourism, port and harbour developments, damming of rivers, urban development and construction, mining, fisheries, aquaculture etc., are all sources of marine pollution threatening coastal and marine habitats.

Effects of Ocean Pollution

  • Effect of Toxic Wastes on Marine Animals: The long term effect on marine life can include cancer, failure in the reproductive system, behavioural changes, and even death.
  • Disruption to the Cycle of Coral Reefs: Oil spill floats on the surface of the water and prevents sunlight from reaching marine plants and affects the process of photosynthesis.
  • Depletes Oxygen Content in Water: Most of the debris in the ocean does not decompose and remains in the ocean for years.
    • Due to this, oxygen levels go down, as a result, the chances of survival of marine animals like whales, turtles, sharks, dolphins, penguins for a long time also goes down.
    • Excessive nutrients from sewage outfalls and agricultural runoff have contributed to the number of low oxygen (hypoxic) areas known as dead zones, where most marine life cannot survive, resulting in the collapse of some ecosystems.
    • There are now close to 500 dead zones covering more than 245,000 km² globally, equivalent to the surface of the United Kingdom.
  • Eutrophication: When a water body becomes overly enriched with minerals and nutrients which induce excessive growth of algae or algal bloom. This process also results in oxygen depletion of the water body.
  • Failure in the Reproductive System of Sea Animals: Chemicals from pesticides can accumulate in the fatty tissue of animals, leading to failure in their reproductive system.
  • Effect on Food Chain: Small animals ingest the discharged chemicals and are later eaten by large animals, which then affects the whole food chain.
  • Affects Human Health

Animals from impacted food chain are then eaten by humans which affects their health as toxins from these contaminated animals get deposited in the tissues of people and can lead to cancer, birth defects or long term health problems.

Global Initiatives

  • The Global Programme of Action (GPA) for the Protection of the Marine Environment from Land-based Activities: The GPA is the only global intergovernmental mechanism directly addressing the connectivity between terrestrial, freshwater, coastal and marine ecosystems.
  • International conventions:
    • MARPOL convention (1973): It covers pollution of the marine environment by ships from operational or accidental causes. It lists various forms of marine pollution caused by oil, noxious liquid substances, harmful substances in packaged form, sewage and garbage from ships, etc.
    • The London Convention (1972): Its objective is to promote the effective control of all sources of marine pollution and to take all practicable steps to prevent pollution of the sea by dumping of wastes and other matter.
  • The Bangkok Declaration on Combating Marine Debris in ASEAN Region was adopted by leaders of the 10-member Association of Southeast Asian Nations, which includes four of the world’s top polluters.The declaration was commended by environmentalists as a good first step for the region, though doubts remained that implementation will be a challenge because the group has a code of non-interference that would leave necessary policymaking in the hands of individual member countries
  • The 1982 United Nations Convention on the Law of the Sea (UNCLOS) was established to protect the marine environment by governing states to control their pollution to the ocean. It put restrictions on the amount of toxins and pollutants that come from all ships internationally.
  • Greenpeace:
    • It is an environmental NGO that is dedicated to conserving the oceans and marine life across the globe.
    • Its grassroots efforts have resulted in the ban of destructive fishing practices, companies changing their fishing policies, and the creation of whale sanctuaries.

How to prevent Ocean pollution?

  • Implement renewable energy sources, such as wind or solar power, to limit off-shore drilling.
  • Proper sewage treatment and exploration of eco-friendly wastewater treatment options.
  • Use of Biotechnology: Bioremediation (use of specific microorganisms to metabolize and remove harmful substances) to treat oil spills.
  • At individual level reduce carbon footprint by adopting a “green” lifestyle.
  • Have a global treaty on banning single-use plastics and collaborated efforts to clean up the ocean.
  • A stricter government regulation on industry and manufacturing is one large scale solution.
  • Implement renewable energy sources, such as wind or solar power, to limit off-shore drilling.
  • Limit agricultural pesticides and encourage organic farming and eco-friendly pesticide use.
  • Cut down on industry and manufacturing waste and contain landfills so they don’t spill into the ocean.

The world’s oceans – their temperature, chemistry, currents and life – drive global systems that make the Earth habitable for humankind. Over three billion people depend on marine and coastal biodiversity for their livelihoods.

In this context, ocean health must be treated as a global issue and all nations should act in concert to implement Sustainable Development Goal: 14 i.e. To conserve and sustainably use the oceans, seas and marine resources for sustainable development.


Ocean Acidification

  • Ocean acidification has been called the “evil twin of global warming” and “the other CO2 problem”.
  • Ocean acidification is the ongoing decrease in the pH of the Earth’s oceans, caused by the uptake of carbon dioxide (CO2) from the atmosphere.
  • An estimated 30–40% of the carbon dioxide from human activity released into the atmosphere dissolves into oceans, rivers, and lakes.
  • To achieve chemical equilibrium, some of it reacts with the water to form carbonic acid(H2CO3).
  • Some of these extra carbonic acid molecules react with a water molecule to give a bicarbonate ion and a hydronium ion, thus increasing ocean acidity (H+ ion concentration).
  • CO2 reacts with water molecules (H2O) and forms the weak acid H2CO3 (carbonic acid). Most of this acid dissociates into hydrogen ions (H+) and bicarbonate ions (HCO3-). The increase in H+ ions reduces pH (measure of acidity) and the oceans acidify, that is they become more acidic or rather less alkaline. This process is called ocean acidification.
  • Checking CO and CO2 emissions and controlling pollution are the only means to reduce ocean acidification.


Consequences of Ocean Acidification

  • Plastic pollution, overfishing, global warming, and increased acidification from burning fossil fuels means oceans are increasingly hostile to marine life
  • Ocean acidification will affect corals. This will, in turn, affect one million species that have made corals their homes.
  • Coral reefs will erode faster than they can rebuild. When shelled organisms are at risk, the entire food web may also be at risk.
  • Some algae and seagrass may benefit from higher CO2 concentrations, as they may increase their photosynthetic and growth rates.
  • Most marine species seem to be more vulnerable in their early life stages.
  • Changes through acidification will be made worse by climate change, pollution, coastal development, over-fishing, and agricultural fertilizers.
  • These changes will affect the many services the ocean provides to us.

Ocean Acidification in Indian Ocean

  • The Arabian Sea is witnessing acidification of its surface waters, a consequence of excessive carbon dioxide in the atmosphere
  • The ocean acidification in the northern Bay of Bengal is mainly due to pollutants mixing with seawater from the Indo-Gangetic plains.
  • During winter, air blowing from land to the sea carries all pollutants with the wind and deposits in the ocean during transit.
  • Study shows rapidly decreasing presence of marine phytoplankton in the western Indian Ocean.
  • A report warns that the Indian Ocean may be reduced to an ecological desert, given the levels of ocean warming.
  • The ocean acidification in the Arabian Sea and Bay of Bengal will devastate one of the most pristine, most fertile regions, the Indian Ocean.


We know that heatwaves occur in the atmosphere. We are all familiar with these extended periods of excessively hot weather. However, heatwaves can also occur in the ocean and these are known as marine heatwaves, or MHWs. These marine heatwaves, when ocean temperatures are extremely warm for an extended period of time can have significant impacts on marine ecosystems and industries.​ Marine heatwaves can occur in summer or winter – they are defined based on differences with expected temperatures for the location and time of year.


We use a recently developed definition of marine heatwaves .

A marine heatwave is defined a when seawater temperatures exceed a seasonally-varying threshold (usually the 90th percentile) for at least 5 consecutive days. Successive heatwaves with gaps of 2 days or less are considered part of the same event.

Impacts of the MHWs

  • Marine heatwaves affect ecosystem structure, by supporting certain species and suppressing others.
  • For example, after the 2011 marine heatwave in Western Australia the fish communities had a much more “tropical” nature than previously and switched from kelp forests to seaweed turfs.
  • Marine heatwaves can cause economic losses through impacts on fisheries and aquaculture.
  • Temperature-sensitive species such as corals are especially vulnerable to MHWs. In 2016, marine heatwaves across northern Australia led to severe bleaching of the Great Barrier Reef.



1. By highlighting the sources of marine pollution, analyze the impact of marine plastic pollution. (250 words)


2) Study the impact of global trade on marine pollution while discussing remedial measures to address the same. (250 words)


3) Marine pollution is said to be affecting not only marine life but life of humans as well. Critically examine the efforts made by international community in addressing the problem of marine pollution around the globe. (200 Words)


4) Examine the impact of marine pollution on coasts and coastal ecology. Also discuss conservation methods to clean coasts. (200 Words)


5) Explain what constitutes Marine litter? And account for the effects it has on Economy and public health. (250 words)


6) By highlighting the sources of marine pollution, analyze the impact of marine plastic pollution.


7) Bring out the various ecological problems associated with the exploitation and use of oceans and their resources?(250 words)


8) Discuss the magnitude and implications of plastic pollution in oceans. (200 Words)


9) Around the world marine habitats are in extreme danger including in India. Examine and comment on the way forward for India when it comes to kickstarting Blue economy?(250 words)


10) What causes acidification of oceans and freshwater bodies? What are the consequences of the same? Examine. (250 Words)




 The OECD defined the process of eutrophication as follows: Eutrophication is an enrichment of water by nutrient salts that cause structural changes to the ecosystem such as increased production of algae and aquatic plants, depletion of fish species, general deterioration of water quality and other effects that reduce and preclude use . For example, the green colour of the Potomac River in the U.S.A had been due to this process of eutrophication leading to excessive growth of cyanobacteria.

Likewise, the process of eutrophication has been witnessed on the coast of Qingdao in Eastern China where children are found swimming in a sea of seaweed.

Both these examples represent an abnormal growth of algae, a clear manifestation of a process called eutrophication.

Eutrophication comes from the Greek word eutrophos which means well-nourished .

In this process, excessive growth of plants and algae take place because of over-supply of nutrients.

This process also leads to oxygen depletion in the water body.

Eutrophication is almost always catalysed by the disposal of nitrate or phosphate-containing detergents, fertilizers, or sewage into an aquatic system.

It promotes overgrowth of plants and algae.

After such organisms die, the bacterial degradation of their biomass consumes the oxygen in the water, thereby creating the state of hypoxia (state of having less oxygen).

Eutrophication can also occur outside water bodies. For example, soils can be eutrophic when they have high levels of nitrogen, phosphorus or other nutrients.

Eutrophication is a critical environmental problem as it leads to a decline in water quality.

According to the Survey of the State of the World’s Lakes, eutrophication affects :

54% of Asian lakes,

53% of those in Europe,

48% of those in North America,

41% of those in South America and

28% of those in Africa

All water bodies undergo a natural and slow eutrophication process which is called natural eutrophication process.

However, in recent decades there has been a rapid increase in the process of eutrophication due to the presence of man and his activities leading to pollution in water bodies. This is called cultural eutrophication.

The cultural eutrophication process comprises of a steady and rapid increase in the contribution of nutrients, mainly nitrogen and phosphorus in water bodies.

This load exceeds the capacity of the water body to purify itself naturally which in turn activates structural changes in the water body.

Such adverse changes are not conducive to the growth of other aquatic organisms.


These structural changes in water bodies occur because of three reasons

  • Use of fertilisers: Agricultural practices like the excessive use of fertilisers in the soil contribute to the stocking of nutrients. A time comes when these nutrients reach high concentration levels and the ground is no longer able to assimilate them, they are carried by rain into rivers and groundwater that flow into lakes or seas.
  • Discharge of wastewater into water bodies: Water pollution is a common phenomenon in various parts of the world, and particularly in developing countries. Wastewater is discharged directly into water bodies such as rivers, lakes and seas. This results in the release of a high quantity of nutrients which leads to excessive growth of algae.
  • Reduction of self-purification capacity: Over the years, lakes accumulate large quantities of sediments. These sediments assimilate large amounts of nutrients and pollutants. This phenomenon results in further deterioration of water quality amplifying the processes connected with eutrophication.



 With the process of eutrophication, the enrichment of water occurs mainly by nutrients such as phosphorus and nitrogen.

An aquatic environment with a limited availability of phosphorus and nitrogen is described as oligotrophic while one with high availability of these elements is called eutrophic .

The intensification of the eutrophication phenomenon produces adverse effects leading to environmental imbalances.

  • The two serious impacts of eutrophication are hypoxia (lack of oxygen) in the deep part of the lake and algal blooms that produce harmful toxins. These developments demolish aquatic life in the affected areas.
  • The substantial loss of aquatic life has a devastating effect on fisheries and the fishing industry. Its adverse impact goes beyond the fishing industry. Recreational fishing which is the backbone of the tourism industry also suffers from a loss of revenues.
  • Algal blooms can have a severe impact on human health. Humans become seriously ill from eating oysters and other shellfish contaminated with toxins produced as a result of the eutrophication process. It can cause eye, skin and respiratory irritation to swimmers, boaters and residents of coastal areas.
  • Fish mortality: Affluence of organic substances leads to deterioration of water quality catalysing threats to fish population in water bodies. This scenario logically leads to an increment in fish mortality.
  • Loss of freshwater lakes: Eutrophication eventually creates a layer of wastes in lakes and produces a successively shallower depth of surface water. Eventually, the water body is reduced into marsh whose plant community is transformed from an aquatic environment to recognizable terrestrial environment.
  • New species invasion: Eutrophication may make the ecosystem competitive by transforming the normal limiting nutrient to abundant level. This causes shifts in species composition of the ecosystem.
  • Toxicity: Some algal blooms (upon death or being eaten) release toxins which can kill aquatic organisms and pose threat to humans. For example, shellfish poisoning.
  • Loss of coral reefs: This can occur due to a decrease in water transparency as a result of eutrophication.
  • Adverse impact on navigation: Affects navigation due to increased turbidity (increased cloudiness or haziness in water bodies).

Thus, it is observed that eutrophication is a threat to the marine ecosystem. Hence, there is a crying need to curb the progress of eutrophication in order to prevent the collapse of the affected marine ecosystems.



How to Control Eutrophication

  • Conventionally, there have been some methods to control/reduce eutrophication viz. the alteration of excess nutrients, physical mixing of the water, application of powerful herbicides and algaecides among others. These methods have proven to be ineffective, expensive and impractical for large ecosystems.
  • Today, the major control mechanism against eutrophication process is premised on prevention techniques like taking out the nutrients that are introduced into water bodies. The strategy is to limit the concentrations of one of the two main nutrients (nitrogen and phosphorus) in water bodies. It is scientifically proven that in particular phosphorus is the main limiting factor for the growth of algae. Hence, when the offload of nitrogen or phosphorus is controlled then there is a visible reduction in the process of eutrophication in water bodies.
  • Increase in efficiency of nitrogen & phosphorus fertilizers and using them only at an adequate level.
  • Reduction in nitrogen emission from vehicles and power plants.
  • There is an ever-increasing population pressure and hence sustained food security will become a more pressing concern. This will magnify the already increasing demands on farmland productivity. But organic farming is very costly and hence farmers will turn to the continued use of phosphate- and nitrogen-rich fertilizers. These fertilizers will catalyse the growth of eutrophic zones. Hence, there is a need to address this dimension of the eutrophication problem.

However, there are cases where water quality is severely compromised and any preventive measures prove to be ineffective. In this scenario, curative procedures can be implemented, such as:

  • removal and treatment of deep water in contact with the sediments rich in nutrients since in direct contact with the release source;
  • drainage of the upper part of sediment subject to biological reactions and with high phosphorus concentrations;
  • oxygenation of water for restoring the ecological conditions,
  • chemical precipitation of phosphorus by the addition of iron or aluminium salts or calcium carbonate to the water,


Practice Questions