Beijing: Beijing city government has issued a red alert for severely high levels of air pollution in the city for five days from late on Friday until Dec. 21, the Beijing environmental protection bureau said on its official Twitter-like Weibo account.

The incoming smog was due to an accumulation of air pollution in Beijing and surrounding areas, including Tianjin city and Hebei, Shandong and Hunan provinces, the post said, citing forecasts from the China Environmental Monitoring Centre.

A colour-graded warning system of alerts was introduced in China’s capital city last year as part of the government vow to crackdown on environmental degradation following decades of unbridled economic growth.

Beijing’s first ever red alert was issued in December last year, temporarily closing schools and halting construction in the city.

The government has since been tweaking the system, raising in February the threshold of issuance to a higher average daily air quality index reading.