Workers can be seen through smog as they walk along a pipeline coming from a nearby rare earth factory in the city of Baotou, located in China's Inner Mongolia Autonomous Region October 31, 2010. The factory refines China's rare earth metals - a market that China has a near monopoly on by producing 97 percent of the world's supply, and having around 87 percent of all known deposits. REUTERS/David Gray (CHINA - Tags: ENERGY ENVIRONMENT BUSINESS)