To match Feature MONGOLIA/POLLUTION.
Smoke billows from the chimneys of a coal-burning power plant in Ulan Bator October 14, 2011. Ulan Bator's pollution is seasonal, with relatively low amounts in summer, but critical levels in the depths of winter when the PM10s can reach 2000 micrograms per cubic metre in the worst affected areas. The 10 most polluted cities on the planet are all in emerging market or developing countries: Iran, Pakistan, India, Botswana and Mongolia. Chronic polluter China no longer has any cities in the top 10. Picture taken on October 14, 2011. To match Feature MONGOLIA/POLLUTION. REUTERS/Carlos Barria (MONGOLIA - Tags: ENERGY ENVIRONMENT) BEST QUALITY AVAILABLE