A report of China's Ministry of Environmental Protection said 14 out of 74 cities passed the government's air quality standards for September.
According to the report, the ten cities with the best air quality include Haikou, Hainan Province, Lhasa,Tibet Autonomous Region, Kunming, Yunnan Province and Zhuhai, Guangdong Province.
Jinan, Shandong Province and Zhengzhou, Henan Province, however, have the worst air quality in September, the report said.
The report shows that about 73 percent of the days in September in Beijing met air quality standards. PM2.5 – particles measuring 2.5 micrometers in diameter – remain as the city's main pollutant but has decreased 25 percent from the same period last year.
Luo Yi, head of the ministry's environmental monitoring division, said the air quality in the Beijing-Tianjin-Hebei area has improved from last year, though the density of some pollutants has increased.
The air quality in the Yangtze River Delta region has also improved compared to the same period last year, while the air quality in the Pearl River Delta region has deteriorated, Luo said.
The National Meteorological Center announced on Tuesday that heavy smog will hit Beijing, Hebei and Shandong for at least five days from Tuesday.
