GUANGZHOU, Jan. 22 -- An odd-even ban on car use will be implemented on heavily polluted days in Guangzhou City of south China's Guangdong Province, the municipal government announced on Wednesday.

According to an emergency response plan on heavy air pollution, cars, including those from outside Guangzhou, will be banned from the road depending on whether their number plates end in odd or even numbers when a red alert is issued.

A red alert, the highest level, will be issued if the air quality index (AQI) exceeds 300 in the following 48 hours. A Grade-1 emergency response will be initiated, the plan said.

Police cars, fire trucks, ambulances, emergency repair vehicles, school buses, buses and taxis are not subject to the ban, it said.

According to local transport department statistics, Guangdong has more than 2.5 million motor vehicles.

Other places in the country, including north China's Shanxi and Hebei provinces, have already introduced odd-even license plate road restrictions on heavily polluted days.

According to the Ministry of Environmental Protection, an AQI of over 300 is defined as "serious pollution" and an AQI between 201 and 300 as "heavy pollution."