BEIJING — Chinese cities continued to see improvement in air quality in the first two months, new data showed.

For 337 cities monitored by the Ministry of Ecology and Environment, the share of average good air quality days stood at 78.3 percent in January-February, up 7.4 percentage points year-on-year, the ministry said in a statement.

The average PM2.5 density, a key indicator of air pollution, decreased by 13.1 percent from a year ago to 53 micrograms per cubic meter in the period, while the average density of PM10 and sulfur dioxide fell 21.3 percent and 20 percent, respectively.

In the first two months, the average PM2.5 density in Beijing-Tianjin-Hebei and the neighboring regions went down 15.7 percent from the same period of last year, with the share of average good air quality days rising 11.6 percentage points to 47.3 percent, the ministry said.

The Yangtze River Delta, another one of the country's most economically vibrant regions, saw the share of average good air quality days increase by 17 percentage points to 80.5 percent, while the average PM2.5 density declined 24.2 percent from the previous year.