BEIJING - Heavy and chemical industries were the main offenders implicated in the recent smog across north China, according to a report published by the Ministry of Environmental Protection (MEP) on Monday.

Based on MEP supervision of six provinces and cities in North China, the report said heavy and chemical industries are scattered all over the place, and this irregular structure was the major obstacle for environmental protection.

Coal consumption provides for almost 90 percent of energy consumption across cities in the north, excluding Beijing and Tianjin, according to the report.

Moreover, coal is still widely used to power heating in the north, instead of green energy. This contributes to the particularly serious air pollution in winter.

The report identified that local administrations could improve the way in which they managed and controlled pollution in suburban areas, as well as how they prevent enterprises from flouting environmental protection regulations.

The MEP on Sunday announced the ten most polluted Chinese cities in November, more than half are in North China.

North China has been choking on heavy smog over the past weeks, with Beijing issuing its first-ever air pollution "red alert," the most serious level, on Dec 7.