Beijing has introduced measures to limit the number of motorists on heavily polluted days, the latest move by authorities in the Chinese capital to battle the choking smog that has blanketed the city in recent years.
Lung cancer rates are rising among the 21 million residents of China's capital, health officials say, with Beijing ranking amongst the world's most-polluted cities.
Earlier this month Premier Li Keqiang pledged to do everything possible to fight pollution, calling it a "blight on people's quality of life".
Motorists will be limited to driving on alternate days when the city announces a "red alert", forecasting heavy pollution for three days, Beijing's environmental protection bureau said in a statement late on Monday.
The bureau defines heavy pollution when the air quality index tops 200, under its four color-coded air quality warning system.
Heavy vehicles including construction vehicles will be banned from the roads during orange or red alerts, the environmental protection bureau said.
The U.S. embassy's air quality index has been consistently in the "unhealthy" range around more than 100 in the past week.
The agency said that "in recent years, the city has continued to increase its air pollution prevention and control efforts by curbing coal and controlling the fuel emissions from cars," among other measures.
"However, currently, the environmental pollutants that are being discharged still exceeds the environment's capacity (to deal with it)," the agency said. "Under extreme adverse weather conditions, it is likely to lead to serious air pollution."
An increasingly affluent urban population has begun to object to China's policy of growth at all costs, which has fueled the economy for three decades.
Environmental awareness has been increasing in China. In late February, Chinese journalist Chai Jing released a new documentary about pollution online, sparking a national debate on environmental problems.
But within a week of its launch, the documentary was inaccessible on the country's video sharing websites, sparking concern from Chinese Internet users that it had been censored.
PHOTO: Buildings are seen from China Central Radio and Television Tower (CCTV Tower) on a polluted day in Beijing, January 15, 2015.
CREDIT: REUTERS/KIM KYUNG-HOON.