December smog hits air quality standards

Frequent severe smog caused more than half of China's 74 major cities to fail national air quality standards in December, the national environmental watchdog said on Monday.

Intense smog blanketed the Beijing-Tianjin-Hebei region on five occasions in the month, making it the most polluted cluster, and Hebei's Baoding and Hengshui cities had eight smoggy days in a row, said Luo Yi, head of the environmental monitoring bureau at the Ministry of Environmental Protection.

The ministry said all 13 cities in the northern cluster experienced soaring concentrations of PM2.5 - particulate matter with a diameter less than 2.5 microns that is hazardous to human health.