Environment

Why Delhi is currently witnessing the worst air quality since 2018

Amid a surge in Covid-19 cases in Delhi, the national capital faces another worrying situation as air pollution levels have also been on the rise.

UPDATED: April 14, 2021 10:16 IST

Amid a surge in Covid-19 cases in Delhi, the national capital faces another worrying situation as air pollution levels have also been on the rise.

Delhi is currently witnessing the worst air quality since 2018, according to an analysis of air quality data of the last one and half months.

The data shows that 2020 was one of the cleanest years in recent times. The nationwide lockdown imposed on March 25, 2020, saw pollution levels in Delhi reducing drastically. As economic activities resumed post lockdown, the air quality started worsening.

Data available through different pollution measuring stations from the capital, established by Delhi Pollution Control Committee (DPCC) and Central Pollution Control Board (CPCB), provides a clear picture of the change in concentration of different pollutants.

Particulate matters are the biggest contributors to Delhi pollution. The main reasons behind the increase in the concentration of PMs include vehicular emission, biomass burning for cooking, electricity generation, smoke released from industries, landfill fire, and episodic agricultural burning.

AIR QUALITY COMPARISON OF 2020 AND 2021

If we compare the average of actual concentrations from all Delhi pollution measuring stations, the PM2.5 concentration in March 2020 was 60.2 µg/m3, while in March 2021, it jumped to 98.2 µg /m3. The average PM2.5 of March 2021 is 63 per cent higher compared to the corresponding period last year.

If we take data of PM2.5 for April, pollution levels in the first week of the month were 120 per cent higher than the corresponding period in 2020. During this period, the average PM2.5 concentration was 91.2 µg /m3 in April 2021, compared to 41.6 µg /m3 in April 2020.

If we take the average of PM2.5 of six weeks (March to April 9) of 2021, it shows a 78 per cent increase in comparison to last year.

If we compare the concentration of larger particulate matter PM10, then a similar result can be found. The average concentration of PM10 in March 2020 was 130 µg /m3, while it was 257 µg /m3 in March 2021.

WHAT DOES DIFFERENCE IN POLLUTION LEVEL MEAN?

Anumita Roy Choudhary, Executive Director of Center for Science and Environment (CSE) and a well-known environmental scientist, explains the difference in pollution levels.

“Pollution levels depend on too many factors, both natural and manmade. Last year during the last week of March we started a complete lockdown due to the covid pandemic. As most of the vehicles were off-road and industries were also shut down, we witnessed a remarkable improvement in air quality. That’s why data for the first week of April has a wider gap in comparison to last year,” Choudhary said.

NATURAL CONDITIONS AFFECTING POLLUTION

This year, even natural conditions remain unfavourable to control pollutants in Delhi-NCR. “This year the number of western disturbances were less and hence the conditions were mostly dry. Last year witnessed quite a few wet spells in the month of March. Apart from that the wind speed remained calm in the first half of March and when the wind speed is slow it is difficult to disburse the pollutants,” said the director of the Indian Meteorological Department (IMD) Kuldeep Srivastav.

Sourcehttps://www.indiatoday.in/cities/delhi/story/why-delhi-is-currently-witnessing-the-worst-air-quality-since-2018-1790672-2021-04-14

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