In its quest for development, China is building highways -- and cars -- at an accelerating pace. There are 26 million cars on the road today, and that number is expected to double by 2010. By then, automobiles are expected to account for nearly two-thirds of China's air pollution.
Some officials, though, are trying to hold the line on auto emissions. The country has recently introduced strict controls. And Beijing has equipped more than 2,500 buses with engines powered by natural gas, at a total cost of $26 million.