It was a Friday of August 2018. The people of Stockholm saw a little girl sitting outside the Riksdagen, the Swedish Parliament, holding a hand-painted banner with "skolstrejk för klimatet" or "school strike for climate" written over it.

The season of festivals is here. But something feels different. My mother tells me that about 25 years ago, the winters would make a precise entry on Dussehra, which usually falls between September and October. A week before Dussehra, we would take the warm clothes out of an old trunk. "Now, it is late November when the weather becomes cold. Only a few days in December are cold enough to wear warm clothes," says my mother.

We read in books that India has six distinct seasons—Grishma seasons (summer), Varsha (monsoon), Sharata (autumn), Hemanta (pre-winter), Shishira (winter) and Basanta (spring)...