China will impose tougher controls on air pollution in Beijing and nearby regions this year to combat heavy smog, closing illegal plants and slashing steel production, a senior environmental official said on Feb 22.

To reduce winter pollution, Beijing, Tianjin and 26 cities in the surrounding provinces of Hebei, Shanxi, Shandong and Henan must attain their annual goals of cutting steel overcapacity ahead of schedule, Zhao Yingmin, vice minister of environmental protection, said at a press briefing.

Those cities should shut down all illegal polluting factories by the end of October and ensure a decrease in their total amount of coal consumption this year, Zhao said.

During the winter heating season, major steel producing cities in Hebei, which is adjacent to Beijing, must cap their output at half of their capacity, he noted.

Meanwhile, cement and casting industries in the Beijing-Tianjin-Hebei region will continue to halt production in winter.

The production controls play a significant role in offsetting pollution in winter, as coal burning for heating usually leads to about a 30-percent increase in pollutant discharge, according to Zhao.

He also demanded clean fuel be used for winter heating and urged stronger measures to curb car emissions.

In 2016, the density of PM2.5, fine particulate matter that causes smog, in the Beijing-Tianjin-Hebei region dropped by over 30 percent from 2013, Zhao said.

However, he noted that the region continued to see frequent heavy pollution in winter and there remained difficulties in tackling the problem.

The share of days with good air quality in the Beijing-Tianjin-Hebei region was merely 36.2 percent in January, a year-on-year drop of 19.6 percentage points, data from the Ministry of Environmental Protection show.

PM2.5 density in Beijing surged 70.6 percent to 116 micrograms per cubic meter during the month, according to the data.