Delhi’s average PM2.5 (a major pollutant) level during winter had improved during the pandemic, however, it has stagnated post the pandemic, according to an analysis by the Centre for Science and Environment.
Actions taken by authorities this winter will determine if the curve will bend or rise further, it said. The analysis has been done for annual and seasonal trends in PM2.5 from January 1, 2015 to October 17, 2022. Winter is considered from October 1 to February 28.
“Overall, long-term data show that improvement made in reducing pollution levels during the winter season has stagnated in the last three years. Smog episodes are again starting to get longer, posing dire threat to public health not just in Delhi but whole of the NCR,” as per the analysis.
Delhi’s seasonal air quality for winter used to hover around 180-190 µg/m 3 before the pandemic but had come down to 150-160 µg/m 3 for the last three winters.
Despite the improvement, the seasonal average is still over 150% – above the 24-hour standard and almost four times the annual standard, the CSE said.
The analysis also noted that air pollution on the night of Deepavali still continues to be a worry.
“PM2.5 concentration on Diwali night (8 p.m. to 8 a.m.) last year stood at 747 µg/m 3, 22% higher than that on 2020 Diwali night. The levels on 2021 Diwali night were 4.5 times the average night-time levels recorded in the week preceding Diwali,” the analysis read.
“This early winter alert is a wake-up call for more stringent pre-emptive and preventive measures to avert the smog episodes that cause excessive exposure and health risk during winter. The enforcement of GRAP needs to be equally stringent with zero tolerance across Delhi-NCR. This requires preparedness in all departments concerned,” said CSE executive director of research and advocacy Anumita Roychowdhury.
Meanwhile, the air quality of Delhi worsened slightly and continued to be in the “poor” category on Thursday. It is likely to be “very poor” on Saturday and Sunday, according to a forecast by the Central government’s Air Quality Early Warning System for Delhi.