India, April 20 -- Seasons shift, and with them come migrations. This cycle is a constant in Mehdi Hasan's life. Until a few months ago, he was hawking roasted peanuts in a city market-that is his winter trade. During the post-monsoon months, he sells roasted bhuttas. Now the city has entered what many consider its most hostile phase: summer. And Mehdi Hasan has again migrated back into selling cool, sweet, refreshing bel sherbet. "That's what I do every summer," he says, his face breaking into a kind, easy smile, as if untouched by the heat, the dust, the chaotic traffic, and the noise of an April afternoon roadside. The soft-spoken gentleman launched the summertime sherbet ten days ago, he says. The setup of Mehdi Hasan's cart is simple: ...