China’s Xinhua news agency said, citing Beijing Municipal Environmental Monitoring Center (BMEMC), that Beijing, Baoding, Handan, Langfang and Hingtai have issued red alerts, the most serious warning level.
The agency added that 13 cities, including China’s northern port city of Tianjin, have issued orange alerts, 17 cities issued yellow alerts, and 5 issued blue alerts.
The agency explained that when a city announces a red alert, the government automatically introduces compulsory measures to alleviate the situation, including reducing car traffic, suspending schools and kindergartens, and temporarily closing companies that emit high volumes of pollutants.
China introduced a four-tier air pollution warning system in 2013. According to the regulations, a red alert can be issued when heavy smog lasts for more than three days, an orange alert for three days of smog, a yellow for two, and a blue for one.