Authorities in China's northern Hebei Province on Wednesday issued an air pollution red alert for heavy smog, the first high-level warning issued by the province this year.
According to the authorities, the smog will hit the province from Dec. 2 to 4. Most cities in the province's central and southern regions are placed under red alert.
In some cities, cars are banned on roads depending on if their license plate ends in an odd or even number; in the city of Xingtai, factories have been told to cut emission by half and construction sites to suspend operations.
Education authorities have not yet decided whether to cancel classes in kindergartens, middle schools and primary schools.
The provincial capital Shijiazhuang's Air Quality Index (AQI) reading reached 466 on Wednesday night. Similar poor readings were recorded in cities of Langfang, Cangzhou, Hengshui and Xinji.
China has a four-tier color-coded system for severe weather, with red being the most serious, followed by orange, yellow and blue. The meteorological authorities issue alerts when the AQI reaches 200 and severe air pollution is forecast to last at least one day.