HARBIN/CHANGCHUN, Oct. 21 (Xinhua) — Heavy smog shrouded northeast China on Monday, forcing the closure of schools, as well as disrupting flights and highways. Meteorological authorities in Heilongjiang, Jilin and Liaoning provinces issued a red alert for thick smog or fog. The fog will worsen in Harbin, Yichun, Daqing, Suihua, Jiamusi and Qitaihe cities in Heilongjiang with visibility of less than 100 meters in the next 24 hours, said the provincial meteorological station. “After walking outdoors for a while, I felt it difficult to breathe,” said Chu Yushu, a resident in Harbin, provincial capital of Heilongjiang, which had visibility of less than ten meters in parts of the downtown area. The density of PM2.5 — airborne particles measuring less than 2.5 microns in diameter, exceeded 500 micrograms per cubic meter early Monday in Harbin. All highways in Heilongjiang and Taiping International Airport in Harbin were closed due to the […]