About a third of the air pollution in China's smog-hit capital comes from outside the city, official media reported on Wednesday, citing a pollution watchdog.

 

Chen Tian, chief of the Beijing Environmental Protection Bureau, said that about 28-36 percent of hazardous airborne particles known as PM2.5 came from surrounding provinces like Hebei, home to seven of China's 10 most polluted cities in 2013, according to official data.

 

The central government has identified the heavily industrialized Beijing-Hebei-Tianjin region as one of the main fronts in its war against pollution, and it is under pressure to cut coal consumption and industrial capacity.

 

Decades of unrestrained growth have hit China's environment hard and Beijing's often choking air has become a symbol of the pollution crisis.

 

Chen said that of the smog generated in Beijing, 31 percent came from vehicles, 22.4 percent from coal burning and 18.1 percent from industry, according to China Environmental News, a publication of the Ministry of Environmental Protection.

 

The city plans to cut coal consumption by 13 million tonnes by 2017, down from about 23 million tonnes in 2013. Hebei province used about 280 million tonnes of coal last year and aims to cut the total by 40 million tonnes over the same period.

 

Beijing also plans to limit the number of cars on its roads to 5.6 million this year, with the number allowed to rise to 6 million by 2017. It is also trying to enforce a ban on old vehicles with lower fuel standards.

 

In 2013, PM2.5 concentrations in 74 cities monitored by authorities stood at an average of 72 micrograms per cubic meter (cu m), more than twice China's recommended national standard of 35 mg/cu m.