A file photo taken on December 17, 2016 shows buildings enveloped in smog in Beijing. [Photo: Xinhua/Jin Liangkuai]

China's environmental protection authority announced Thursday that 28 northern cities are aiming to lower a major air pollution indicator by at least 15 percent this coming winter.

Between October 2017 and March 2018, China will reduce the level of PM 2.5 pollution by at least 15 percent in the cities around the Beijing-Tianjin-Hebei region, according to a plan released by the Ministry of Environmental Protection.

During that period, the number of heavily-polluted days will also be cut by more than 15 percent compared with one year earlier, the ministry said.

The ministry will intensify air quality monitoring, deal with companies operating unauthorized locations, lacking relevant certificates, or failing to meet emission standards, and control coal consumption in the region.

According to the plan, an organization will be set up to coordinate efforts to combat air pollution in the Beijing-Tianjin-Hebei region and surrounding areas. It is expected to start trial operation before the end of September.

Winter typically brings higher air pollution to northern China because of a combination of weather conditions and an increase in the burning of coal for heating systems.