Air pollution killed more Indians last year than any other risk factor, and Delhi is among the most polluted cities in the country. But the burden is unequally shared.

Children from poor families in Delhi spend more of their lives outdoors. Their families are more likely to use wood-burning stoves, which create soot. They can’t afford the air filters that have become ubiquitous in middle-class homes. And often, they don’t even think much about air pollution, because they face more pressing threats, like running out of food.

Money can buy a family less exposure to Delhi’s deadly pollution — but only to a point. Air purifiers and well-sealed rooms can do only so much. Though precise estimates are impossible, even well-off kids like Aamya could lose roughly a year of life because of the amount of toxic air they breathe. And Aamya has asthma, so her parents are especially concerned.

Still, over the course of one day, Monu was exposed to about four times as much pollution as Aamya. A long-term, consistent disparity like that could steal around five years more life from someone in Monu’s position, compared with an upper-middle-class child like Aamya….