Air pollution in China is at dangerous levels. Grey smog covers Beijing. It is difficult to breathe. It threatens to block President Xi Jinping's vision. He has popularised the idea of a "Chinese dream". His dream involves increasing wealth at home and increasing power abroad.

However, the leadership needs to rethink its national goals. After all, what is the point of rapid economic growth if it creates cities in which it is dangerous to breathe?

Air pollution might have caused about 1.2 million premature deaths in China in 2010 alone. Beijing has registered a 60% rise in lung cancer cases in the past decade.