More severe smog is forecast to blanket northern China from Friday until Monday, the national meteorological authority said on Thursday.
Weakening winds will see the pollution get gradually worse until it reaches a peak on Sunday and Monday, according to the National Meteorological Center.
Beijing, Tianjin and parts of Hebei, Shanxi, Henan and Shaanxi provinces will be the worst affected.
Visibility in these regions could be as low as between 1 and 2 kilometers, the center said, adding that the peak concentration of PM2.5 -- fine particulate matter with diameter of 2.5 microns that is hazardous to human health -- is expected to be in excess of 400 micrograms per cubic meter in some cities in Hebei.
The pollution is expected to clear starting Monday night, when more wind is forecast.
