India’s capital halted construction and shut schools after the city was enveloped with toxic smog. Its roads were bustling with traffic and the occasional water sprinklers mounted on trucks were deployed to reduce dust.

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.