According to the national air quality situation in July 2019 released by the Ministry of Ecology and Environment, the top 10 are Haikou, Zhuhai, Lishui, Huangshan, Shenzhen, Zhongshan, Lhasa, Xiamen, Zhoushan and Taizhou.

In July 2019, the average proportion of good days in 337 cities at prefecture level and above nationwide was 85.4 percent, down 6.9 percentage points year-on-year; PM2.5 concentration was 20 micrograms per cubic meter (μg/m3), flat year-on-year; and PM10 concentration was 40 μg/m3, up 5.3 percent year-on-year.

The O3 concentration was 146 micrograms per cubic meter, up 8.1 percent year-on-year; the SO2 concentration was 8 micrograms per cubic meter, down 11.1 percent year-on-year; the NO2 concentration was 19 micrograms per cubic meter, up 11.8 percent year-on-year; and the CO concentration was 0.8 milligrams per cubic meter, down 11.1 percent year-on-year.

The average proportion of good days in July in the "2+26" cities in Beijing-Tianjin-Hebei and neighboring regions was 38.6 percent, down 28.7 percentage points year-on-year, with O3 as the main pollutant; PM2.5 concentration was 34 micrograms per cubic meter, down 2.9 percent year-on-year.

Beijing's proportion of good days in July was 38.7 percent, down 25.8 percentage points year-on-year, with O3 as the main pollutant; PM2.5 concentration was 37 micrograms per cubic meter, down 15.9 percent year-on-year.

The average proportion of good days in 41 cities in the Yangtze River Delta region in July was 81.9 percent, down 9.9 percentage points year-on-year; the PM2.5 concentration was 23 micrograms per cubic meter, up 9.5 percent year-on-year.

The average proportion of good days in 11 cities in the Fenwei Plain in July was 57.2%, down 20.8 percentage points year-on-year, with O3 as the main pollutant; the PM2.5 concentration was 25 micrograms per cubic meter, down 19.4% year-on-year.

In July 2019, among the 168 key cities, 20 cities, including Tangshan, Jincheng and Xingtai City, had relatively poor air quality (from 168th to tied 149th); 20 cities, including Haikou, Zhuhai and Lishui City, had relatively good air quality (from 1st to 20th).

Expanded:

Air quality in 142 cities nationwide reached the standard in the first half of 2019:

According to the national air quality situation in January-June 2019 released by the Ministry of Ecology and Environment. The average proportion of good days in 337 cities at prefecture level and above nationwide was 80.1%, up 0.4 percentage points year-on-year; the ambient air quality of 142 cities reached the standard, up 20 year-on-year; the PM2.5 concentration was 40 micrograms per cubic meter, down 2.4% year-on-year; and the PM10 concentration was 69 micrograms per cubic meter, down 4.2% year-on-year.

The ozone concentration was 143 micrograms per cubic meter, flat year-on-year; the sulfur dioxide concentration was 12 micrograms per cubic meter, down 14.3 percent year-on-year; the nitrogen dioxide concentration was 27 micrograms per cubic meter, flat year-on-year; and the carbon monoxide concentration was 1.5 milligrams per cubic meter, up 7.1 percent year-on-year.

The average proportion of good days in the "2+26" cities in the Beijing-Tianjin-Hebei and neighboring regions was 47.5%, down 2.3 percentage points year-on-year, while the PM2.5 concentration was 66 micrograms per cubic meter, up 4.8% year-on-year. In Beijing, the proportion of good days was 62.4%, up 2.7 percentage points year-on-year; the PM2.5 concentration was 46 micrograms per cubic meter, down 13.2% year-on-year.

The average proportion of good days in 41 cities in the Yangtze River Delta region was 73.6 percent, down 0.2 percentage points year-on-year; the PM2.5 concentration was 47 micrograms per cubic meter, down 4.1 percent year-on-year.

From January to June 2019, the air quality of 20 cities among 168 key cities, including Linfen, Xingtai and Shijiazhuang City, was relatively poor; and the air quality of 20 cities, including Haikou, Lhasa and Shenzhen City, was relatively good.

From the degree of year-on-year improvement in air quality, from January to June, the air quality of 20 cities among the 168 key cities, including Nanning, Suzhou, Zhaoqing, etc., improved relatively well; and the air quality of 20 cities, including Tai'an, Dalian, Linyi, etc., improved relatively poorly.

China News Network - Ranking of national air quality conditions in the first seven months released

People's Daily Online - Air quality in 142 cities nationwide reaches standards in the first half of 2019