The Ministry of Ecology and the Environment on June 21 published a report on the national ambient air quality of 168 major cities in May. Zhongshan was once again among the top ten in terms of air quality, ranking the third nationwide.

About 87.8% of days in May held an average of "good" or higher in its air quality across 339 prefecture-level Chinese cities, up 2.2 percentage points from the previous year; the average concentration of PM2.5 was 22 μg/m³, down 8.3%, and the average concentration of ozone was 143 μg/m³, down 6.5%.

Among the 168 major cities, Haikou, Zhuhai, Zhongshan, Lhasa and Shenzhen had seen relatively good air, while Taiyuan, Linfen, Xianyang and Shijiazhuang had poor air quality.

The notable improvement of air quality in Zhongshan is owed to various implemented measures citywide, including deeper cooperation among districts and towns, strengthened comprehensive regulations for high-emission enterprises, control over the generation and emission of VOCs (volatile organic compounds) and NOX (nitrogen oxides), and promotion of the transformation and upgrading of enterprises to more efficient and environment-friendly production methods.