Beijing, Feb 5 (IANS): China's ministry of environmental protection (MEP) announced that overall air quality had improved in 2015, the media reported on Friday.

Luo Yi, MEP head of environmental monitoring, said 338 cities were monitored in 2015. Among them, only 73 cities - mostly in Fujian, Guangdong, Guizhou and Yunnan provinces, and Tibet - had met national standards, the Global Times reported.

Luo said there were "signs of improvement".

The density on PM2.5, or particles measuring less than 2.5 microns in diametre, dropped 14.1 percent from the previous year in 74 key cities in 2015, and readings of PM10 fell by 11.4 percent.

Of the 74 cities, Haikou, Huizhou, Lhasa, Xiamen and Zhoushan registered the best air quality, while Baoding, Hengshui, Tangshan and Xingtai - all in Hebei province - along with Zhengzhou in Henan province were the most polluted.

Nationwide, the average PM10, or particles with diameters less than 10 microns, sulfur dioxide and nitrogen dioxide readings dropped by 7.4, 16.1 and 6.3 percent, respectively, in 2015.