Delhi's AQI reached 376 on Sunday as Diwali celebrations began under dense smog. Forecasters expect severe pollution as emissions rise and weak winds trap pollutants. Delhi entered Diwali under a blanket of smog on Sunday, with air quality already ‘very poor’ and forecast to turn ‘severe’ after the evening’s celebrations.Weak winds were expected to trap pollutants, adding to concerns over firecracker smoke, vehicle emissions and stubble burning.