BEIJING - The Ministry of Environmental Protection (MEP) on Thursday said air quality checks would be intensified in 2015.

According to the MEP, 14 inspections were made by the ministry in 2014, including to the city of Tianjin; North China's Inner Mongolia autonomous region; and Hebei, Shanxi and Henan provinces.

Follow-up surveys showed that air quality in those regions had improved remarkably, said Liu Changgen, a director with the ministry's inspection department.

But the situation is far from perfect, Liu said, pointing to insufficient desulphurization facilities at heating plants in some regions.

He also noted excessive discharge of pollutants by certain enterprises, explicitly naming Zhengzhou Xinli Electric Power Co Ltd for its oxynitride discharge.

This year the ministry will organize further, stricter inspections in the above regions as well as include other cities on its inspection program.

Levels of PM2.5, a key indicator of air pollution, and ozone have been included in air quality standards since 2013.

Tianjin and the cities in Hebei and Henan provinces and in Inner Mongolia frequently top the MEP's monthly air pollution lists.