BEIJING, Oct. 22 (Xinhuanet) -- Winter typically brings the worst air pollution to north China because of a combination of weather conditions and an increase in the burning of coal for homes and municipal heating systems.
In the northeastern city of Harbin, the city’s heating systems kicked in on Sunday, and on Monday visibility there was less than 50 meters. The level of PM 2.5 particles was greater than 500 micrograms per cubic meter in most urban areas, far above safe levels.
Some buses stopped running and airports were temporarily closed. Classes in all primary and middle schools too had to be suspended.