View caption Ng Han Guan/AP
Skyscrapers are obscured by heavy haze in Beijing on Jan. 13. Air pollution remains a serious, sometimes overwhelming, problem, but researchers say environmental technology is available to solve it.
There is some political willingness, but because China is highly decentralized politically the Communist Party has only limited influence over provincial governments and how they regulate their dirty factories. The powerful state-owned oil companies have also resisted pressure to produce cleaner-burning fuel.