Beijing, Tianjin and Hebei and their neighboring regions in North China will experience another round of severe air pollution, which is forecast to start from Saturday to Tuesday (Dec 1), the national environmental watchdog said on Friday.

The region will see air pollution reaching the top two hazardous levels during the four days, because of the disadvantageous weather, which will not disperse the pollutants.

Besides, the increasing emission of air pollutants from coal-fired boilers and other sources for heating is another major reason for the coming smog, the Ministry of Environmental Protection said.

The new round of smog is forecast to cover the vast northern region including Beijing, Tianjin, Hebei,the western part of Shandong province, and the northern part of Henan province.

Luo Yi, head of environment monitoring bureau under the ministry said the air quality was expected to improve after Dec 2 with better weather conditions to disperse pollutants.

The ministry requires the affected regions to take emergency efforts including suspension of work at construction sites and industrial restrictions to cut emissions.

Beijing has issued the yellow alert on Friday afternoon.

It has sent four inspection teams to Beijing, Tianjin, Shijiazhuang and Langfang, two cities in Hebei province on Friday to supervise efforts to curb the pollution.