Highways, Airports in East China Shut Due to Thick Fog

, Nov 22: A heavy fog shrouded many parts of east

's Shandong province on Saturday, closing highways, delaying flights and throwing normal life out of gear.

The provincial meteorological observatory issued a yellow alert for heavy fog early this morning, forecasting visibility of less than 500 meters in the northwestern and northern areas of the Shandong province.

Beijing has four levels of warning for air pollution. Red is the highest, followed by orange, yellow and blue. The system was introduced last year and a red alert has not yet been issued.

More than 70 toll stations of 11 highways in Shandong had to be temporarily closed, transport officials said.

Flights were also hit due to low visibility at the international airport of the provincial capital Jinan. So far about 20 flights have been postponed or cancelled, state-run Xinhua news agency reported.

Chinese capital Beijing, however, saw a clear day this morning after two days of choking smoggy weather.

Though, Beijing and its neighbouring areas are likely to soon face another bout of persistent heavy air pollution for up to five days, according to the Ministry of Environmental Protection.