Beijing's environmental protection bureau's deputy director Du Shaozhong said the city will adopt stricter vehicular restrictions during periods of heavy air pollution.
While all cars will be restricted from driving at least one weekday depending on the last digit of their license plate numbers, during periods of heavier pollution, an even-odd license plate number rule would ban half the capital's 3.4 million cars from the roads.
"To protect public health over the long term, we must use both methods that increase the number of good air quality days and more stringent measures for when conditions are extremely unfavorable," Du said.
Unfavorable air quality is exacerbated by low air pressure, heavy fog and thick haze.
In addition, work will be suspended at construction sites and plants that produce high levels of pollution.
When these conditions threaten air quality, causing the air pollution index (API) to reach at least 300, the government will notify the public of a ban two days in advance.
Bureau sources said the measures were similar to emergency plans drawn up for, but not used during the Games.
The city will develop further measures after the car ban takes effect on a trial basis tomorrow - to run for the next six months until April.
"The new plan will produce results at the current stage," Zhu Tong, a Peking University professor advising the local government on Beijing's pollution control, said.
"But Beijing is a drastically changing metropolis. It's not easy to draw up a long-term plan at any time," he said, adding the environmental bureau listened to experts' opinions after drafting the plan.