GUANGZHOU - Fewer government cars will be allowed on the road on heavily polluted days in Guangzhou, South China's Guangdong province, according to new measures being considered by the city government.

The traffic control plan requires half of all government cars to be off the road when there is a red alert for air pollution. Currently, 30 percent of government cars have to be off the road when there is a red alert.

In addition, the remaining government vehicles should follow odd- and even-numbered license plate rules. This means all cars, including those from outside Guangzhou, are only allowed on the road depending on whether their number plates end in odd or even numbers.

The plan means only a quarter of government cars will be on the road when there is a red alert for air pollution, an official with the city's environment protection department, told Xinhua on Tuesday.

The government will issue a red alert, the highest level, if the air quality index (AQI) exceeds 300.

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

The new plan has been publicized on the environment protection department's website. Citizens can provide opinions before March 6.

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

Other places in the country, including Beijing, 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".