60 cities were affected by a bout of severe air pollution in the Beijing and Tianjin areas during the weekend, triggering the first use of a new warning system in the Beijing-Tianjin-Hebei region.
The unified grading system was adopted at the end of October to standardise air pollution warning systems in all three cities, which used different warning systems. The four-tier system uses red to represent the most severe air quality, followed by orange, yellow and blue.
Red alerts are issued if the Air Quality Index (AQI) is predicted to reach 500 and last for over a day, or if the AQI is predicted to be higher than 200 for three days in a row.
Beijing & surrounding rustbelt "broke the index" first time this winter, air pollution above 500 where official index ends pic.twitter.com/QFOvpq0d2i
— Lauri Myllyvirta (@laurimyllyvirta) December 3, 2016
Between Friday and Sunday, red warnings were raised in nine cities in Hebei. Orange warnings were raised in 24 cities including Beijing and Tianjin, yellow warnings were raised in 22 cities in Henan, and five blue warnings were issued in Shandong province, according to state-backed news outlet The Paper.
The Beijing Municipal Environmental Protection Bureau cited a rise in temperature and humidity and mainly southerly winds as reasons for the poor dispersal of the smog.
Coal-fired power plant south of Beijing. Orange alert for air quality this weekend. pic.twitter.com/saVI9Fvb7X
— Tom Fletcher (@tomfletcherbc) December 2, 2016
It called for a halt to demolitions, earthworks, concrete pouring, and other construction activities to mitigate the smog on Friday. Inspections on construction sites, industrial enterprises and high-emission vehicles were carried out in the capital, The Paper reported.
Visibility decreased to one to two kilometres, with visibility of less than 500 metres in some parts of the city. Several highway sections were closed in Hebei to reduce traffic, and some flights flying to and out of Tianjin were delayed due to the smog.
The Ministry of Environmental Protection sent inspection units to Hebei and Shandong to inspect the response of local governments and small enterprises, The Paper reported.
The air in Beijing improved on Monday as a cold front cleared the smog.