Delhi PM2.5 pollution in winters has dipped 20% compared to pre-pandemic period: CSE

New Delhi: The average PM2.5 pollution in Delhi in the winter season has declined by about 20 per cent as compared to the pre-pandemic period, according to a new report released by the Centre for Science and Environment (CSE) on Thursday.

It also said Diwali this year is being observed early in the season "which means the warmer and windier conditions will help dilute the pollution that is staple of Diwali night celebrations". However, concentrated stubble burning due to prolonged rains (in September end and October) may compound the problem.

The assessment captured seven successive winters and pre-winter trends, starting from January 1, 2015 in Delhi and the National Capital Region (NCR). It is based on real time data available from the 81 operational air quality monitoring stations in the region.

The PM2.5 concentration for winter (October 1 to February 28) used to hover around 180-190 microgram per cubic metre before the pandemic. It has come down to 150-160 microgram per cubic metre since then, the report said.

Anumita Roychowdhury, executive director of research and advocacy at the CSE, said the objective of the report is to understand the trend and "the starting line of the onset of the winter pollution season or pre-winter levels in this region".

The seasonal average is still over 150 per cent above the 24-hour standard (60 microgram per cubic metre) and almost four times the annual standard (40 microgram per cubic metre) despite the improvement, the green thinktank noted.

It said peak pollution showed a similar trend as the seasonal average.