JINAN, Nov. 22  -- A heavy fog shrouded many parts of east China's Shandong Province on Saturday, closing highways and delaying flights, said local transport and airport sources.

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

More than 70 toll stations of 11 highways in Shandong had to be temporarily closed. Flights were affected at the international airport of the provincial capital Jinan due to low visibility. As of 9:20 a.m., about 20 flights have been postponed or canceled.

Chinese capital Beijing saw a clear day on Saturday morning after two days of choking smoggy weather.

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