Alert issued as smog shrouds Beijing

Beijing issued a yellow alert for smog on Thursday for the first time since October when the city drew up an emergency plan featuring a four-color alert system.

A red alert signals the highest level of pollution, ahead of orange, yellow and blue alerts.

The city's environmental protection bureau forecast that the smog will last for three days and suggested the public use public transportation instead of private cars to help ease pollution caused by exhaust emissions.