Delhi witnessed a ‘polluted’ spring this year. As per the latest air quality analysis report January–March recorded higher levels of pollution for the season since 2019.

While there was a substantial drop in PM2.5 levels during both the hard lockdown phases in March-May 2020 and April-June, this year, with nearly similar levels evoking the imagery of a blue sky, the early months of 2021 witnessed worsening of the air quality.

“This indicates that despite the partial restrictions the pollution levels have increased. While the reason needs investigation, it is important to underscore that there would be a rebound effect with full opening of the economy and intensification of traffic. Pandemic management during the second wave may have slowed down action but this has to speed up to prevent the rebound effect or retaliatory emissions to ensure longer term air quality gains”, said Anumita Roychowdhury, executive director-research and advocacy, CSE.

“This is particularly important given the new science on the linkage between air quality and its effect on vulnerability to the pandemic,” she added.

According to environmentalists, spring acts as transitional period between the two extremes – winter and summer. A significant drop in PM2.5 levels happens as the weather warms up and wind picks up speed during spring.

“There was a 26 per cent drop between the winter of 2018 and spring of 2019. In 2020 this drop increased to 36 per cent due to pollution control measures in place and also imposition of partial lockdowns in March 2020. But this downward trend in spring pollution did not continue this year, with the seasonal drop limited to 18 per cent. In fact, spring this year has been 31 per cent dirtier than 2020 and eight per cent dirtier than 2019,” the CSE report said.

On Delhi and the National Capital Region (NCR), the CSE also marked that during 2020-2021, at least 14 additional locations have registered higher seasonal average than the mean of recognised hotspots, making them the new hotspots. Three locations each were added in the hotspot category in Ghaziabad and Noida.

During this May’s lockdown, Panjabi Bagh, Rohini and Dilshad Garden have recorded improvement compared to the May 2020 lockdown. But RK Puram, Patparganj, Sadipur, and Mandir Marg have worsened.

Interestingly, the number of days in severe and severe plus categories stabilised in 2020, but the number of days in very poor category increased this year.