Coal Stoves Make Ulaanbaatar the World's Most Polluted City

The 1.3 million people who live in Mongolia's capital city of Ulaanbaatar breathe the dirtiest city air in the world. It's a public health nightmare, and winter means facemasks, asthma and pneumonia. There is a solution, but it requires changing an ancient way of life for half of the city's residents. VOA's Kevin Enochs reports.