India, Feb. 26 -- In the sun-baked expanse of Mahabubnagar district in Telangana, November brings a trickle of relief. Morning mist clings to trees and crop fields. By mid-morning, though, the winter whispers retreat before the assertive sun, and the landscape shimmers in heat. It makes N Jogaiah Babu's morning trudges to the field easier. His village is a jumble of modest single-story houses, their walls a patchwork of limestone wash and broken bricks, lining narrow alleys that wind like dusty ribbons.

An agricultural labourer with a smattering of land holdings, Babu doesn't walk back from the fields till the sun is searing overhead. But one late November day, the mobile phone in his pocket started buzzing even before noon. It was his w...