Updated Mar 04, 2021 | 09:37 IST Most improvement was noted at NSIT Dwarka, Wazirpur and Shadipur, the CSE said, adding that the maximum increase was noted at Patparganj, Vivek Vihar and R K Puram (all residential areas). Delhi NCR pollution today  New Delhi: Seasonal average of winter pollution in Delhi-NCR in 2020-2021 was higher than in the previous year but the severity and duration of smog episodes was lower, a new analysis by environment think tank Centre for Science and Environment (CSE) said on Wednesday. For the purposes of implementation of the Graded Response Action Plan (GRAP), winter in the region is officially demarcated as the period from October 15 to February 1, the CSE said.