Yellow haze alert as smog shrouds Shanghai

Shanghai is severely polluted Thursday as cold air brought smog from North China. The Shanghai Meteorological Bureau issued a yellow haze alert at 7:41am in the morning, the lowest of a three-level warning system.

Shanghai's Air Quality Index soared to 216 by 11am into the zone of heavy air pollution, the bureau said.

The smoggy weather will continue in the afternoon and the city's AQI is expected to hover between 320 to 350. PM2.5 pollutants, airborne particles less than 2.5 micrometers in diameter, are listed as the main source of pollution.

But there will be some relief tomorrow and the mercury will drop to zero over the weekend.