Moderate to heavy air pollution is likely to affect central and southern parts of the Beijing-Tianjin-Hebei region over the next three days, the Ministry of Environmental Protection said on Tuesday.

Parts of east China's Shandong Province and the central province of Henan will also be hit by smog during the period, the ministry said, citing a forecast by the China National Environmental Monitoring Center (CNEMC).

On Monday, air pollution affected 100 of 338 cities monitored across the country. Northwest China's Xinjiang Uygur Autonomous Region and east China's Anhui Province suffered the most.

As of 12 a.m. on Tuesday, three cities in the Beijing-Tianjin-Hebei region -- Beijing, Shijiazhuang and Hengshui -- were experiencing moderate air pollution while the air in the other 10 cities in the region was graded "good" or "light pollution."

The CNEMC began issuing air quality forecasts for key regions and major cities at the start of this year. Updates can be found at www.cnemc.cn.