China smog crisis: Visibility at record lows, highest alert in place as winter peaks

China is experiencing some of the worst levels of air pollution that has resulted in heavy smog. As of Wednesday Beijing was under a "red alert" for smog, the highest of four levels and a "yellow alert" for fog. Some other areas are still under red alert for both smog and fog. The authorities ordered the highways closed in and around the city due to smog crisis.

Several leading airports have cancelled flights as China's weather bureau warned of visibility of less than 50 m in some areas. The Beijing Evening News reported more than 2,000 tourists were stranded on a cruise ship for two extra days near the port of Tianjin. Until Monday, the ship was prevented from docking due to smog.

Northern China is quite known for pollution alerts, especially during bitterly cold winters. Colder temperatures mean more coal is burned to heat homes, which exacerbates the nation's air pollution problem. But, this time the smog alert is at the second-highest orange only and has raised several serious questions.

This is the third year when China is fighting the pollution war and is trying to reverse the damage that has been done to its skies, soil and water after decades of untrammelled economic growth.