Nestled in a valley in central Chile, near lakes and snowcapped mountains, sits one of the world’s most polluted cities. Every winter, sleepy Temuco plunges to the bottom of global air quality rankings. While notoriously polluted megacities such as Beijing and New Delhi have populations almost 100 times that of the tiny Chilean town, contributing to round the clock traffic and factory activity, Temuco’s contamination doesn’t come from economic activity. It comes from poverty.

June though August, when the Southern Hemisphere is in winter, thermometers in Temuco drop to as low as 4º Celsius (39º Fahrenheit). Poor temuquenses, as the city’s 220,000 residents are known, have no choice but to burn cheap—often wet—firewood to keep warm.

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Smoke raises from a chimney of a house in Temuco.
Photographer: Luis Hidalgo/AFP/Getty Images

From the window of her living room, 60-year-old resident Patricia Bravo says she can sometimes only see half a block down the street in her Temuco neighborhood. The rest is all gray smoke. “It’s like living in a city with permanent fog, except it’s chimney smoke,” says Bravo, who’s lived there since she was a young girl. She’s gotten used to itchy eyes and the smell of heavy smoke in her living room this winter, she says, even when her own chimney is dark and her windows are closed.