A man wears a face mask to protect himself from the air pollution in downtown Shanghai, Jan 24, 2013. [Photo/Agencies]

BEIJING - China issued a blue-coded alert on Sunday as foggy weather forecast for the coming two days will cut visibility and worsen air pollution in some central and eastern Chinese cities.

The alert represents the least serious level, after red, orange and yellow in China's four-tier color-coded weather warning system.

The National Meteorological Center (NMC) said visibility in provinces including Hebei, Henan, Shandong, Jiangsu, Anhui and Zhejiang will be cut to less than 1,000 meters on Sunday. In some cities, where fog will be thicker, visibility will fall below 200 meters.

The NMC warned of a decline in air quality and advised residents in these regions to stay indoors as much as possible or take precautions.

Meanwhile, a strong cold front will cause snowfall and temperature drops in Xinjiang Uygur Autonomous Region, with some parts experiencing blizzards and temperatures plunging more than 10 degrees Celsius, it forecast.