Car pollution isn’t the major pollutant for Beijing, it’s more industrial, power production, and heating (coal); a lot of drifts in from Hebei and gets trapped in Beijing because it is shaped like a bowl. Cars have fairly good emissions in the jing, while the gas is kept clean also. You can actually see the pollution spike higher at night when the cars are mostly off the road and blue trucks come in from hebei without emissions equipment using crappy gas.

http://www.wri.org/blog/2008/07/beijings-air-pollution-it-is...

Electric cars will help for sure, but it isn’t going to solve the problem on its own. Shifting away from coal (especially for heating, especially in the Hebei country side), and getting factories in Hebei to obey the law is much more important.