Pavadairayan, 60, a migrant laborer known as a "basket man," carries fish in a basket on his head from boats to the auction house at Kasimedu Fishing Harbour in Chennai, India.

Pavadairayan, 60, a migrant laborer known as a "basket man," carries fish in a basket on his head from boats to the auction house at Kasimedu Fishing Harbour in Chennai, India.

In the bustling heart of the southern Indian city of Chennai is a market that never sleeps, where residents from the poorest neighborhoods wage a battle of survival with the sea.