Xinhua News Agency, June 19, the Ministry of Ecology and Environment announced the national air quality situation from January to May. The average number of days of excellent air quality in cities at and above the prefecture level decreased by 3.1 percentage points compared with the same period last year. From January to May, the average number of days of excellent air quality in 339 cities at prefecture level and above was 82%, down 3.1 percentage points from the same period last year, and the average number of days of severe pollution and above was 3%, up 1.6 percentage points from the same period last year. The average concentration of PM2.5 was 38 micrograms per cubic meter, up 8.6 percent from the same period last year. From January to May, the average number of days exceeding the standard caused by sand and dust weather in 339 cities at prefecture level and above was 6.3%.