China has met its annual target for pollution control, but challenges still remain, Chinese Ecology and Environment Minister Li Ganjie said on Sunday at the "Ministers' Corridor" during this year's Two Sessions.

Last year, the average PM 2.5 density (a key indicator of air pollution) in 338 major cities decreased by 9.3 percent year on year, and that of Beijing dropped by 12.1 percent, Li introduced.

"We have successfully met all the targets set for 2018 and stayed in line with the timetable outlined by the 13th Five-Year Plan," he said. 

Despite the progress, the minister warned that China still faced lots of difficulties and challenges in this area, and the situation remained grave. 

Pollution control is one of the "three tough battles" for the next three years set by the 19th National Congress of the Communist Party of China (CPC) in 2017, and the ministry will continue its efforts. 

This year, China will put the Yangtze River restoration project in full swing, clean up more "black and malodorous" water bodies in cities, achieve environment improvement in the Bohai Sea, and strive for a better environment in rural areas, according to the minister.