The Beijing municipal government officially put into effect an emergency program on Tuesday to deal with air pollution.

According to the Beijing Municipal Heavy Air Pollution Emergency Response Program, drivers will only be allowed to use their cars every other day when a red air pollution alert is issued. Cars with odd and even license plates will be allowed on alternating days and 30 percent of municipal cars will be banned from streets on an odd/even basis.

The emergency response will remind citizens to protect themselves from health hazards and take strict emission reduction measures.

During a red alert, kindergartens, primary and high schools will be suspended, and some industrial plants shut down.

Fang Li, deputy chief of the city's environmental protection bureau, said the bureau would try its best to issue warnings 24 hours before heavy days.

An air quality index (AQI) of over 300 is defined as "serious pollution" and an AQI between 201 and 300 is considered "heavy pollution."

Vehicles are considered a major contributor to Beijing's heavy smog. A research team from the Chinese Academy of Sciences estimated that vehicle exhaust fumes contribute 22.2 percent of PM 2.5 particles -- particles under 2.5 microns in diameter -- in the city, exceeding the figure for industrial emissions.

It is estimated that the public transport system will have 2 million more passengers on an emergency day, Fang Ping, deputy director of Beijing Municipal Commission of Transport, told a press briefing on Tuesday afternoon.

This requires additional buses, trains and trams. Public transport will be extended by 30 minutes to cope with the pressure, said Fang Ping.