Lingering smog has disrupted traffic in northeast China's Heilongjiang Province, closing highways and affecting flights.
Readings of PM2.5, airborne particles smaller than 2.5 microns in diameter, hit 244 micrograms per cubic meter in Heilongjiang's capital city Harbin as of 7 p.m. Wednesday. The World Health Organization set the maximum for human health at 25 micrograms on a 24-hour average.
Slashed visibility, coupled with days of snow, has forced some major highways to close in the city, including the Jingha Highway linking Harbin and Beijing.
Poor air conditions have affected flights, with 109 flights canceled as of 3 p.m., according to the local airport. The local meteorological center issued a blue alert for heavy air pollution for the next 48 hours on Wednesday afternoon. The provincial meteorological center has issued warnings for coming fog in Heilongjiang on Wednesday night and Thursday morning.
Heavy air pollution also affected traffic in the cities of Daqing and Suihua, local authorities said.
The foul air in northeast China will continue until Nov. 14, partially fueled by burning coal for public heating, according to the Ministry of Environmental Protection.
"Most areas" in Liaoning, Jilin and Heilongjiang province will see medium to heavy air pollution, with PM2.5 being the main pollutant, the ministry said.
Heavy smog hit the region in early Nov., roughly the same time coal heating begins in north China.