Krishna Koli is 10, lives in Delhi, falls ill frequently and rarely steps out of home. On a day when the Capital’s air pollution levels peaked to record levels, Ankita Upadhyay tracked his journey — from an asthma clinic in a government hospital to his home on the outskirts of the city,

Whatever the causes of the smog, by one ranking Delhi was not just the most polluted city in the world, but “nearly five times as bad as the second most polluted city, Dhaka,” in Bangladesh next door, as Shashi Tharoor, a leader of the opposition in Parliament and best-selling author, posted on X.