BEIJING - Air quality improved in Chinese cities in the first five months of 2019, according to the Ministry of Ecology and Environment (MEE).

Some 337 Chinese cities enjoyed good air quality on 80.3 percent of days from January to May this year, up 0.6 percentage points from the same period last year. Nearly 120 cities met the air quality standards, including 20 cities joining this year, data of MEE showed.

The average PM2.5 density, a key indicator of air pollution remained unchanged at 44 micrograms per cubic meter over the period and the average density of PM10 and sulfur dioxide fell 2.6 percent and 13.3 percent respectively year-on-year.

Haikou, Lhasa and Shenzhen ranked top three on the list of 168 cities' air quality in the first five months while cities in the provinces of Hebei, Henan and Shanxi lagged behind.

Several regions saw a decrease in PM2.5 in May 2019, with that in Beijing-Tianjin-Hebei region and Yangtze River Delta down 16.7 percent and 8.6 percent year-on-year respectively.

China pledged to coordinate its efforts on environmental protection and economic development in 2019.

The country vowed to reduce imports of solid waste and push for better air quality with better regional coordination and heavy-polluter revamps, according to the ministry.