BEIJING, June 5 -- China has reported better performance on environmental protection in 2023, with continued improvement in air and water quality, according to a communique released by the Ministry of Ecology and Environment on Wednesday.

For the 339 cities monitored by the ministry, the average density of PM2.5, a key indicator of air pollution, was 30 micrograms per cubic meter in 2023, almost 3 micrograms per cubic meter down from the annual target, according to the ecology and environment communique released on the ministry's website.

The figure has seen a plummet of 28.6 percent since 2016, reflecting a trend of continued improvement in air quality.

In terms of surface water, 89.4 percent of monitored sections had fairly good quality -- at or above Grade III in the country's five-tier water quality system, up 1.5 percentage points year on year.

The communique also revealed that the proportion of seawater areas under China's jurisdiction with top quality stood at 97.9 percent, up 0.5 percentage points year on year.

Wednesday marks World Environment Day, a United Nations day for encouraging worldwide awareness and action to protect the planet's environment.

This year's World Environment Day focuses on land restoration, desertification and drought resilience.

China has restored over 100 million mu (about 6.7 million hectares) of ecosystems that include mountains, rivers, forests, farmlands, lakes, grasslands and deserts, said an official with the Ministry of Natural Resources during a themed activity held by the United Nations Environment Programme China Office on Monday.