 "Air quality tied to lung problems in children")
Pollution woes of Beijing and several other Chinese cities continued as they remained in the worst air quality list in China.
Beijing and its neighbouring Hebei Province had the worst air quality in China in July, the Ministry of Environmental Protection said on Friday.
The Chinese capital, a city of over 20 million, is ranked ninth among the nation's ten cities with the worst air.
Eight of the ten most polluted cities are in Hebei province, namely Xingtai, Hengshui, Baoding, Tangshan, Shijiazhuang, Handan, langfang and Cangzhou.
Jinan, capital of east China's Shandong Province, is ranked fifth.
Monitoring data shows that the percentage of the days recorded with excellent or good air quality in 13 cities across the Beijing-Tianjin-Hebei region was 54.4 per cent, a decrease of 0. 4 percentage points year on year.
The percentage for Beijing was 31 per cent with a drop of 4.5 per cent points.
Ozone and PM 2.5 were the two primary pollutants.
On the whole, nationwide air quality improved, said Luo Yi, director general of the ministry's department of environmental monitoring.
A total of 74 Chinese cities are regularly ranked in this monthly survey.
The cities of Haikou, Zhuhai and Zhoushan, mainly in the country's southern or eastern coastal regions, topped the list of 10 cities with the best air quality, state-run Xinhua news agency reported.
They were followed by Guiyang, Lishui, Lhasa, Nanning, Xiamen, Kunming and Zhongshan.
