All over the world cities are grappling with apocalyptic air pollution but the small capital of Mongolia is suffering from some of the worst in the world.
And the problem is intrinsically linked to climate change.
The country has already warmed by 2.2 degrees, forcing thousands of people to abandon the countryside and the traditional herding lifestyle every year for the smog-choked city where 90% of children are breathing toxic air every day.
Population Reporter Stephanie Hegarty finds out why.
Mongolia: A toxic warning to the world