Most cities in the country saw an improvement in air quality last month, the Ministry of Ecology and Environment said in its monthly report on Friday.

In the 337 cities measured, an average of 88.3 percent of the days in March recorded good air quality, an increase of 5.1 percentage points compared to that in March last year.

The report said the average PM2.5 density nationwide fell by 4.7 percent year-on-year to 41 micrograms per cubic meter.

In the Beijing-Tianjin-Hebei cluster, an average of 74.5 percent of the days in March had good air quality, up 20.8 percentage points than March last year. The average PM2.5 reading was 54 micrograms per cubic meter, down by 28 percent year-on-year.

Although southern China reported better air than the north, it nevertheless was not as good as the previous year. The Yangtze River Delta region had an average of 84.2 percent of days of fresh air last month, down 3.1 percentage points than March 2018.

Fenhe-Weihe River Plain area, which includes 11 cities in Henan, Shanxi and Shaanxi provinces, made the biggest year-on-year improvement among all regions last month. With an average of 79.2 percent of days in March having good air quality, an increase of 26.1 percentage points year on year. The average PM2.5 density was 47 micrograms per cubic meter for March, down by 35.6 percent year-on-year.