China's central government announced a fresh round of environmental targets in September. The new blueprint sets a nationwide goal to cut the concentration of harmful particles in the air by at least 10% over the next four years, compared to 2012 levels.

The targets are even more ambitious in heavily polluted regions. In northern China -- including Beijing, Tianjin and Hebei -- the goal is to cut the level of particles by 25%, while in Shanghai and the Yangtze River Delta the target is 20%.