BEIJING, April 21 (Xinhua) -- Air quality in China continued to improve with reduced pollution, the country's top environment official said Sunday.

In 338 Chinese cities, 121 met the air quality standards in 2018, said Li Ganjie, the country's Ecology and Environment Minister, in a report submitted to China's top legislature for review at its ongoing bimonthly session.

According to Li, air quality significantly improved in key regions, although heavy pollution still took place during autumn and winter.

The average density of PM2.5, a key indicator of air pollution, dropped 11.8 percent year on year in 2018 in the Beijing-Tianjin-Hebei region and its surrounding area.

The 338 cities on average saw more days of good air, Li said.