Every winter Delhi is engulfed by smog. Air quality drops to a very poor or severe category. The 2020-21 winter also coincided with opening up from the COVID-19 lockdown. While economic activity has still not reached its peak, air pollution in Delhi was only marginally better than the previous year. The number of smog episodes was lower than the previous two years. However, the seasonal average was higher than the previous two years. Anumita Roychowdhury, executive director-research and advocacy talk about the Centre for Science and Environment's latest study on 2020-21 winter pollution.