Air pollution in Mongolia's capital, Ulan Bator, is among the world's worst. A thick haze often envelops the city, reducing visibility to just 20 meters. The main problem is smoke from coal-burning stoves. The number of such stoves has increased as more migrants move to the city in search of work. City officials are now trying to tackle the problem by convincing people to replace their old stoves. In this episode, we look at the battle to bring clear skies back to Ulan Bator.
