SHIJIAZHUANG, Nov. 27 (Xinhua) -- North China's Hebei Province, home to more than half of the country's 10 worst-polluted cities, is taking measures to clean up its air.

In a meeting on Wednesday, the Hebei provincial government ordered a 521 companies in the highly polluting industries of steel, cement, power generation and glass to boost efforts to reduce emissions of pollutants.

Yang Chongyong, executive vice governor of Hebei, told the meeting that the four sectors are the main sources of pollutants in the province, home to seven of the country's top 10 polluted cities in the third quarter of the year.

Last year, the four sectors consumed 167 million tonnes of coal, 53 percent of the total demand in Hebei. They also emitted 65.4 percent of its total sulfur dioxide, 60.2 percent of its nitrogen oxide and 61 percent of its total dust.

The latest move came as the Chinese central government is getting more serious in tackling air pollution as the choking air has become the target of growing discontent among urban residents.

A large swathe of east China was affected by smog for long periods earlier this year, prompting more public complaints and thus government actions. Several regions in northern China, including Beijing, Hebei and Tianjin, have been worst hit.

In September, the State Council, or the cabinet, signed air pollution control initiatives with six provinces and municipalities in north China, including Beijing, Tianjin, Hebei, Shanxi, Inner Mongolia and Shandong, in a coordinated effort to tackle severe air pollution.

Amid the ensuing measures, the Hebei provincial government has pledged to cut its annual steel production capacity by 60 million tonnes by 2017 and to reduce its annual coal consumption by 40 million tonnes from 2012 levels under the same time frame.

Hebei is ready to help improve the environment in Beijing and its surrounding areas even at the cost of gross domestic product (GDP) and fiscal revenues, said the vice governor.

The four polluting sectors have made great contributions to GDP and jobs creation, but "in the fight against pollution, we are left with no escape route but have to fight to win," said Yang.

Companies in the four sectors are ordered to improve pollutant treatment facilities to prevent half a million tonnes of sulfur dioxide, nitrogen oxide and dust from being emitted into the air each year from 2015.

Also the provincial authorities ordered some companies to switch to gas from coal to power their operations.

Meanwhile, pollutant emissions will be closely monitored by local environmental protection authorities, and anyone who secretly discharges pollutants is subject to severe punishment including jail terms.