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Light pollution: The dark sky is a natural resource, and too much light is polluting it

GS Paper 3

Syllabus: Conservation, Environmental Pollution and Degradation


Source: TH


Direction: The article seeks to discuss light pollution, its causes, effects, and recommendations for reducing it.



  • In 2022, the district administration of Ladakh in India created the Hanle Dark Sky Reserve (HDSR) which is the first International Dark Sky Reserve in India. The HDSR comprises six hamlets within the Changthang Wildlife Sanctuary.
  • The reserve thus had a responsibility to keep the skies dark, particularly for the astronomical observatories located in the area.


What is a Dark Sky Reserve?

  • It refers to an area designated as free from light pollution. It’s a public or private land possessing an exceptional or distinguished quality of starry nights and nocturnal environment that is specifically protected for its scientific, natural, educational, cultural, heritage and/or public enjoyment [IDA-International Dark-Sky Association].



  • When SpaceX’s Starlink constellation of small satellites started to block ground-based telescopes’ views of the Earth, the notion that the sky is a natural resource that could be harmed, gained popularity.
  • These incidents also highlighted the need for a global agreement to reduce light pollution.
  • However, while authorities actively work to reduce light pollution around telescope sites, the night is actually getting brighter (skyglow) in almost all of the world, with significant ecological, health and cultural ramifications.


What exactly is light pollution and how bad is it?

  • Light pollution is excessive, misdirected or obtrusive artificial (usually outdoor) light that obstructs starlight in the night sky, interferes with astronomical research, disrupts ecosystems, has adverse health effects and wastes energy.
  • Visible light emitted by many sources (except lasers) is divergent, so the light emitted could find its way into the sky.
  • Almost all surfaces in cities also reflect light, meaning a portion of entirely down-cast light will be reflected upwards, contributing to nighttime light pollution.
  • A recent study found that non-natural light had increased the brightness of the artificial glow of the night sky, or skyglow, by 9.2-10% every year between 2011 and 2022. Specifically, it had brightened annually by about 6.5% over Europe, 10.4% over North America, and 7.7% over the rest of the world.



What is the situation in India?

  • A recent study reported that 19.5% of India’s population – the lowest among G20 countries – experiences a level of skyglow that keeps the Milky Way out of sight and makes it impossible for human eyes to adjust to the dark.
  • The effects include stimulating the cone cells (which activate in a well-lit environment/during the day) in human eyes.



What are the consequences?

  • Harms wildlife and disrupts ecosystems: Light pollution poses a serious threat in particular to nocturnal wildlife, having negative impacts on plant and animal physiology. For example,
    • It can confuse the migratory patterns of animals.
    • A 2020 study noted that skyglow interferes with multiple aspects of insect life and allows insect predators to hunt for longer.
    • A 2019 study reported that clownfish eggs don’t hatch when exposed to artificial light at night, killing the offspring.
    • At their meeting in Gandhinagar (2020), parties to the Convention on Migratory Species adopted guidelines to address this issue.
  • Adverse effects on human health: It can disturb circadian rhythms and the production of melatonin, leading to sleep disorders and other health problems (increased risk of breast cancer).
  • Energy wastage: lighting is responsible for at least one-fourth of all electricity consumption worldwide. Thus, energy wastage is also a waste in cost and carbon footprint.



Way ahead: Light pollution can be reduced easily by shielding lights properly, by

  • Only using light when and where it is required,
  • Only use the necessary amount,
  • Using energy-efficient bulbs, and
  • Using bulbs with the right spectral power distributions.
  • International Best Practice: The “Outdoor Lighting Code” in the United Kingdom, aims to reduce light pollution by encouraging the use of lighting that is only as bright and as long as necessary for the task.


Conclusion: “The erasure of the night sky acts to erase Indigenous connection to the stars, acting as a form of ongoing cultural and ecological genocide.”



Components of light pollution include:

  • Glare – excessive brightness that causes visual discomfort
  • Skyglow – brightening of the night sky over inhabited areas
  • Light trespass – light falling where it is not intended or needed
  • Clutter – bright, confusing, and excessive groupings of light sources


Insta Links:

Environmental Pollution


Prelims Links: (UPSC 2020)

Which of the following are the reasons/factors for exposure to benzene pollution?

  1. Automobile exhaust
  2. Tobacco smoke
  3. Wood burning
  4. Using varnished wooden furniture
  5. Using products made of polyurethane

Select the correct answer using the code given below:

  1. 1, 2 and 3 only
  2. 2 and 4 only
  3. 1, 3 and 4 only
  4. 1, 2, 3, 4 and 5


Ans: 1