Delhi gets cleanest Sept air in 9 yrs, PM2.5 in safe zone
40 industrial units sealed in Mandoli
New Delhi: If you found something very unusual about the clear blue skies and fresh air in the capital this September, you were right. This was the cleanest September the city has seen in at the last nine years for which Delhi Pollution Control Committee (DPCC) data is available.
TOI analysed DPCC data from 2011 to 2019 and found that both the average PM2.5 and PM10 levels were within safe standards for the first time during September in all these years. While the average PM10 level was 99 micrograms per cubic metre (as against a safe standard of 100), average PM2.5 level was recorded at just 40 micrograms per cubic metre, well below the safe limit of 60.
This was a slight improvement from last September, when the average PM10 concentration was 121 micrograms per cubic metre and PM2.5 was 44 micrograms.
“Meteorological conditions have certainly played a part this September but if you look at trends from 2015 onwards, there has been a gradual decline each year,” said Mohan George, head of DPCC’s air division.
“Pollution was at its peak in 2015. Since then, not only has coordination on the ground improved but there is better preparedness from us and other agencies. Violators are being fined on the spot and there is greater deterrence,” George added.
In September 2015, the average PM10 concentration was 239 micrograms per cubic metre, while the average PM2.5 level was 72 micrograms. Compared to then, PM10 concentrations have declined by 58% and PM2.5 has come down by 44%.
The change in pollution levels has also been significant in terms of the Air Quality Index, which was started by Central Pollution Control Board in 2015. The average AQI for September has also been coming down gradually since 2015, with the lowest of 98 recorded this year — the first time since data collection when average air quality was “satisfactory”.
The average AQI was 194 in September 2015, 162 in 2016, 139 in 2017 and 112 in 2018.
While an AQI reading of 50 or below is classified as “good”, readings between 51 and 100 fall in the “satisfactory” category and those between 101 and 200 are classified as “moderate”. “Poor” air ranges from 201 to 300, “very poor” from 301 to 400 and “severe” from 401 to 500.
Delhi recorded also recorded no “poor” days in September this year with the highest AQI recorded on September 4. In fact, 19 days in the month were classified Average* PM10 (μg/m³) concentration in September (2011-2019) ➤ Average AQI levels in September have been coming down gradually since 2015 with the lowest average recorded this year at (162 in Sept 2016, 139 in 2017, 112 in 2018)
as “satisfactory” – meaning the AQI was below 100. The remaining 11 days were in the “moderate” range.
Anumita Roy Chowdhury, executive director, research and advocacy at the Centre for Science and Environment (CSE) said while the longterm data analysis shows a downward trend, the monthly averages are influenced both by proactive action and meteorological conditions.
“The annual averages are coming down if you look at the long term data and the number of severe days has also reduced. In September, both meteorological conditions and kick starting action early has helped. This makes a strong case for ensuring that October is also better than the last few years. With the Graded Response Action Plan (GRAP) kicking in soon, we can certain control the Delhi
Pollution Control Committee said that it had sealed 40 industrial units in Mandoli Industrial Area from September 27 to September 30 for causing air pollution and not following environmental norms. The list of units were identified as those which had either not switched to cleaner fuels, like PNG, or were clandestinely using other fuels. DPCC said, as part of the action plan, such drives will continue in other parts of Delhi.
peaks,” said Chowdhury.
Dipankar Saha, former head of CPCB’s air lab said rains, not so much in the capital but in the surrounding areas, played a part in controlling dust pollution. “An extended monsoon has meant dust has been kept under control. However, ground level action has improved over the last few years and both these factors are going hand-in-hand to help Delhi,” Saha added.