Seven provinces reached their pollution reduction goals months ahead of schedule, a new report said on Wednesday. The targets set for 2017 were met in 2016, it said.

All major pollutant levels have fallen as a result of efforts to combat smog, as indicated by monitoring data released by governments and environmental bureaus nationwide, according to the Innovation Center for Clean-Air Solutions, an environmental NGO based in Beijing.

The report focused largely on levels of PM10 and PM2.5 - fine, hazardous particulate matter - which are used as major indexes for air quality in China.

The seven areas - Anhui, Sichuan, Jiangxi, Heilongjiang, Guizhou and Guangdong provinces and the Guangxi Zhuang autonomous region - have all met their targets for reducing PM10, it said.

However, northern regions, including Beijing, Tianjin and the provinces of Hebei, Shandong and Shanxi, still face severe smog during the heating season, the report said, adding that the average PM2.5 level during that period was almost double all other times of the year.

Controls introduced by provincial governments have worked to reduce air pollution, but more are needed in winter, including more scientific research into the causes of air pollution, it said.