Air pollution is once again surging in Delhi. It’s part of a larger pollution problem in India. The massive spike in noxious air in the national capital and its surroundings is not entirely from stubble burning in adjoining states but also owes its genesis to predominant local pollution sources, and is compounded by unfavorable meteorology of the city. Air pollution peaks in Delhi and surrounding regions every winter, when pollution from stubble burning combines with the suspended water droplets in the lower atmosphere to form a thick blanket of noxious smog, thus creating health hazards. This surge in air pollution in Delhi is an alarmingly regular occurrence, and it’s part of a dangerous pollution problem in India. The World Health Organization reported last year that 11 of the 12 cities in the world with the most pollution from PM2.5 — particles smaller than 2.5 microns in diameter that can cause dangerous heart troubles and breathing problems — were in India. The Lancet Commission on pollution and health found that in 2015, there were 9 million premature deaths stemming from air pollution around the world. India suffered the worst toll of any country, with more than 2.5 million of these deaths. Pollution has also shaved 3.2 years from the life expectancies of 660 million people in the country, according to one estimate.