GS Paper 1
Syllabus: Geographical phenomenon and their environmental impacts
Direction: The article mainly highlights how local winds like sea breezes could influence the pollution level of a place.
Context: Over the last month, air quality in India’s financial hub, Mumbai, has been noticeably worse than in prior years, giving Mumbaikars a taste of what people in Delhi have become used to at this time of year.
Background: Since December 5, the AQI in Mumbai has consistently been in the “very poor” range (AQI > 300), according to the SAFAR (System of Air Quality and Weather Forecasting and Research) network.
Why is this unusual?
- This is not the first time Mumbai’s air has been so toxic, but it has never lasted more than 1-2 days.
- Though Mumbai generates pollutants in equivalent amounts as compared to Delhi, it has an important location advantage.
- Mumbai’s relatively clean air is the result of strong sea breezes that sweep air pollutants away from the land.
Reasons for this unusual pattern:
- Change in flow patterns: In Mumbai, winds move from land to sea for a few days and then from sea to land and this cyclic pattern usually repeats every 3-4 days.
- When the wind is not moving away from the land, air pollutants accumulate over the city. But then the wind direction changes, and it all gets cleaned.
- This cycle is delayed this year. Instead of repeating every 3-4 days, it is happening after a week, even 10 days.
- Even when the wind direction turns favourable, the lack of adequate speed means that the air is not entirely cleaned.
- Though the meteorological reasons behind this change needed to be probed, this can be attributed to some unusual global events like the third consecutive year of La Niña.
- La Nina is an abnormal cooling of the Pacific Ocean that impacts weather events across the world.
- More construction activities: Large infrastructure projects, like the Mumbai Metro or the Coastal Road Project, could be generating significantly higher amounts of pollutants.
- This could be possible, as Mumbai is currently witnessing a rise in PM10 (particulate matter of the size of 10 micrometres or smaller) levels as well.
Q. Explain local winds and how they impact the weather condition of a region? (250 words)