Beijing has issued its first air pollution red alert of the year, with the most severe smog since autumn set to start on Friday night and last for five days.

Another 22 northern cities have been advised to follow the capital and issue the highest emergency response, the Ministry of Environmental Protection said on Thursday.

The red alert, effective from 8 pm Friday, will see tougher restrictions introduced for private car owners, who will be allowed to drive only on alternate days depending on their license plate number, the Beijing municipal government said.