BEIJING, May 29 (Xinhua) -- China's ecological and environmental quality kept improving last year, according to a report released by the Ministry of Ecology and Environment Wednesday.

Some 338 cities enjoyed good air quality on 79.3 percent of days in 2018, up 1.3 percentage points from a year earlier, said the report.

The concentration of fine particles declined 9.3 percent year on year to 39 micrograms per cubic meter last year.

Water quality also improved, with 6.7 percent of surface water sections identified as the worst level, down 1.6 percentage points from the previous year.

The ministry on Wednesday also released a communique on China's marine ecology and environment. Inshore waters of good quality accounted for 74.6 percent, up 6.7 percentage points from the previous year.

Heavy pollution, however, was found in parts of Liaodong Bay and Bohai Bay, the marine environment communique said.