Coal is big in Montana. There are vast coal beds in eastern Montana and the northeast corner of Wyoming. Much of that coal moves through Missoula on a regular basis bound for shipping ports on the West Coast. A large share of that coal is bound for China. Shanghai, China has some of the worst, if not the worst air pollution in the world.  During a recent several day period the air was so thick reports said you couldn’t see 30 feet, the airport was shut down, and people were told to stay home. Now it appears officials have plans to correct the situation. They’re set to ban coal burning in just four years, according to a new Clean Air Action Plan. The city-wide ban on coal burning is one effort among many to get Shanghai's infamous smog under control. The ban will require the city's 2,500 coal boilers and 300 industrial furnaces to either shut down or shift to cleaner energy by 2015.