Meteorological conditions in northern China are unfavorable for the dispersal of air pollutants, and it will be heavily polluted till Tuesday, the China National Environmental Monitoring Center said on Thursday.

It said air pollution in the Beijing-Tianjin-Hebei region will not be eased until the arrival of cold winds on Sunday.

However, the PM2.5 level in the provinces of Shandong, Henan, Shanxi and Shaanxi will peak on Sunday due to high humidity and temperature inversion, the center said. With the arrival of cold winds, pollutants in these areas will be dispersed on Tuesday.

The Ministry of Ecology and Environment has sent warning letters to local governments in those four provinces plus Hebei, urging them to ask industries to reduce emissions and inform residents about pollution.