(WANG KAI)

Vehicles move slowly through dense smog in downtown Harbin, northeast China's Heilongjiang Province, on October 22. Meteorological authorities in the province issued an air-quality red alert for the city and neighboring regions.

All schools in Harbin were ordered to suspend classes. The city's expressways and airport were also closed.

At the same time, severe smog shrouded other major cities in the country's northeast, such as Changchun, capital of Jilin Province, and Shenyang, capital of Liaoning Province.