A woman with a bike passes by the main electric factory of Lanzhou, Guo Jian, which uses cial a s energy source and is one of the main source of pollution of the town. China.
Lanzhou, in the Gansu province is the most polluted cities of China and in the world's top ten for atmospheric pollution due to human activity. The town is situated between two hills along the Yellow River and the polluted clouds remain blocked over the town. The sky is most of the time hidden by the pollution.