Nanjing, capital of east China’s Jiangsu Province, has ordered schools suspended today, citing a red alert for haze as persistent choking weather lingers in 25 provincial areas.

The order applies to kindergartens, primary schools and middle schools, Nanjing’s publicity department said, after the city’s air quality index had hit 484.

In the east coast city of Qingdao in Shandong Province, authorities tightened supervision of heavy polluters including coal-fired boilers and construction sites while restricting the use of government vehicles.

Outdoor school activities had been canceled since Tuesday.

China’s meteorological authority yesterday issued two yellow alerts for fog and haze, both the lowest in a three-level system, for the third consecutive day.

Heavy fog is forecast in central Yunnan Province, southwest Sichuan Basin, eastern regions in Guizhou Province, eastern and northern Anhui Province, western and northern Fujian Province and most areas in Jiangsu, according to the National Meteorological Center.

Visibility would be less than 500 meters in some areas.

Moderate haze is forecast to last until 8pm today in southern Tianjin, southern Shandong Province, northern parts of Zhejiang Province, southern parts of the Sichuan Basin and eastern and northern areas of Jiangsu and Auhui provinces.