Four degrees of alert warnings based on the severity of air pollution, together with corresponding measures, are set to be launched by the Beijing government under the air pollution emergency response plan passed on Wednesday.

The plan did not include a timeline for implementation, but an anonymous press officer with the Beijing Municipal Bureau of Environmental Protection told the Global Times Thursday that it is likely to be released by the end of this month.

The new plan, passed by the Standing Committee of the Beijing Municipal CPC Committee, the city's top leadership, represents alerts with four colors, namely red, orange, yellow and blue, the Beijing Daily reported Thursday.

Red alerts will be issued when the city's pollution level goes beyond 300 PM2.5 (particular matter of 2.5 microns or less) on the air quality index.

On red alert days, classes will be suspended in schools. Trucks transporting sandstone or debris, which can easily produce dust, will be banned during the most polluted days. The already-existing odd-even license plate restrictions will also be tightened.

The existing restrictions mean each driver is banned from the road on one out of every five weekdays. But under the red alert, they will face a 50 percent chance of being banned from the road during periods of heavy smog.

In addition to cutting half of the government vehicles on the road under this rule during polluted days, 30 percent more government cars will also be banned from the roads at the same time.

The city will see an estimated 2 million more passengers turn to public transport due to the traffic controls and 21,000 to 25,000 buses will be allocated to the current public transport network to ease the traffic pressure, according to the plan.

Ma Jun, director of the Institute of Public and Environmental Affairs in Beijing, said it is important to make sure these tough measures are really implemented. He said that removing 80 percent of government cars from the roads during red-alert days will be a daunting task with uncertainty in terms of enforcement and supervision.

The measures in the plan will see an immediate effect in the short term in regard to tackling pollution problems, but they are only provisional ones to combat smoggy days, Zhang Kai, a representative in charge of climate and energy issues at Greenpeace, told the Global Times.