At least 10 Chinese cities issued red alerts for smog on Thursday, with more than 100 million people being warned to stay indoors, state media reported. According to AFP, the smog covered large parts of the country’s eastern and central areas, including the province of Shandong, which is home to almost 96 million people. Measures to curb the toxic haze were ordered to be implemented.

On Friday, Beijing had issued its second red alert for pollution, after residents of North China were warned of choking smog. The capital cancelled the red alert at midnight on Tuesday. The city had declared its first red alert last week after being criticised for not issuing it during previous bouts of smog. A government issues a red alert when it believes air quality will reach very unhealthy levels.