Coal is China's most important energy commodity. It accounts for the majority of energy consumption, and China produces and consumes almost as much coal as the rest of the world combined.  Such levels of coal production raise economic activity, but at the same time, the large consumption levels have contributed to elevated levels of air pollution. This pollution has recently led authorities to "declare war" on smog, and the Chinese government anticipates boosting natural gas consumption in place of coal in response. In this paper we consider the implications of such switching for economic activity, energy production and consumption, and emissions in China, as well as for the global coal and natural gas markets.