A Bad Night's Sleep Might Do More Harm Than You Think

"It's 11 at night in a busy commercial section of Chennai, a city of nearly 5 million in Southern India. All around me people are sleeping in the open air. Men are curled up in the back of rickshaw wagons. Entire families camp out in shelters made of cardboard and tarp. A woman in a blue sari smiles and waves for me to come over."

"She tells me her name is Anjalai — like some in this part of India, she goes by only one name — and says she's got the most basic setup: a woven blue mat laid out on a patch of dirt by the side of the street."

"I ask her, 'What's it like to sleep in this spot?'"

"Her smile fades."

"'It's difficult', says Anjalai. 'There's so much noise from vehicles coming through.'"

The traffic isn't the half of it. People have tapped the power lines to hook up televisions right on the street — the blare echoes late into the night. Drunks wander by, shouting incoherently. Loudest of all: the dogs.