A new-energy truck is assembled at a factory in Northwest China's Shaanxi province, Aug 27, 2012. [Photo/Xinhua]

People walk on a bridge in Taiyuan, capital of North China's Shanxi province, May 10, 2012. Taiyuan, one of China's coal mine hubs, used to be heavily pollution, but the city's environment has been greatly improved thanks to local government's efforts, such as water treatment, moving polluting enterprises out of city, and removal of villages in the city. [Photo/Xinhua]