BEIJING -- High-emission vehicles will be taken off all roads in Beijing to help control smog, a local government official said Wednesday.

A new action plan will be made to fight air pollution, with grass-root enforcement efforts to be further strengthened, said Chen Jining, acting mayor of Beijing, at the opening of the first annual session of the 15th Beijing Municipal People's Congress.

Currently, vehicles with high emissions are forbidden within the Sixth Ring Road.

Vehicle exhaust, industrial emissions and coal use are among the causes of air pollution, and analysis into pollutant formation will help root out significant pollution sources.

This year, smog control in the capital will be based on the analysis of the sources of PM2.5 pollutants, said Chen, pledging all-out efforts to reduce the average PM2.5 density.

The average density of PM2.5 in Beijing was 58 micrograms per cubic meter last year, meeting the target set by the State Council and 20.5 percent less than in 2016.