Smoke billows from chimneys at a chemical factory in Hefei

 
Smoke billows from chimneys at a chemical factory in Hefei
Smoke billows from chimneys at a chemical factory in Hefei, Anhui province March 10, 2010. China's top climate negotiator said on Wednesday that the cause of global warming was still not clear but the problems it is creating are so enormous that the world must anyway act to cut greenhouse gas emissions now. REUTERS/Stringer (CHINA - Tags: ENVIRONMENT BUSINESS IMAGES OF THE DAY)