BEIJING - A total of 24 Chinese cities are on red alert due to serious air pollution, which will affect many people's new year holiday plans.

Cities including Shijiazhuang, Baoding and Langfang in northern Hebei province, Zhengzhou in central China's Henan province and Jinan in eastern China's Shandong province, have issued red alerts for severe air pollution, according to China's top environmental watchdog.

Moreover, 21 metropolises and cities including Beijing and Tianjin, have issued orange alerts for air pollution, while 16 cities including Xi'an in northwestern Shaanxi province are on yellow alert.

The new round of air pollution is forecast to last until Jan 5 in most cities, said the Ministry of Environmental Protection.

A total of 10 inspection teams from the ministry have been dispatched to different provincial regions to supervise the implementation of environmental measures taken by key industrial enterprises, the ministry said.

China has a four-tier warning system for severe weather, with red being the most serious, followed by orange, yellow and blue.

Measures such as suspension of school classes and restriction of cars will be adopted in red alert areas.