Delhi is choking under a thick blanket of toxic smog ahead of Diwali, with the AQI at India Gate touching 399. The national capital recorded its worst air quality in 288 days, as the average AQI soared to 377. Stubble burning in Punjab and Haryana has added to the pollution, prompting authorities to issue notices to officials in five Punjab districts. With winter approaching, Delhi-NCR faces another season of hazardous air.