Major parts of eastern and central China were shrouded under a thick layer of haze and fog on Saturday while pollution in the capital city of Beijing was at 'hazardous' levels.
Several flights were cancelled and 20 highways were closed in eastern China where visibility levels dropped drastically.
Hebei and Henan provinces were among the most polluted areas, the state media said.
Beijing was also engulfed by a heavy smog for a second day today, and the capital city's air quality was rated as "hazardous".
"The smoggy weather will not clear up until Monday," the city's environment monitoring center said, adding Beijing's air is heavily polluted.
The elderly, children and those suffering from respiratory and cardiovascular diseases were advised to stay indoors to reduce exposure to polluted air, state-run Xinhua news agency said.
Meanwhile, heavy fog blanketed Hebei, Tianjin, Shandong, Henan, Jiangsu, Anhui, Jiangxi and Hubei provinces.
In Shandong, more than 20 highways were closed, as the fog reduced visibility in some areas to less than 50 meters, the provincial meteorological centre said.
A total of 63 flights in and out of Shandong's eastern coastal city of Qingdao had been cancelled or delayed by 2 pm today, affecting about 5,000 passengers, according to airport administration authorities in Qingdao.
In Jiangxi, visibility in eight cities was reduced to less than 500 metres. The fog forced five highways to close and delayed dozens of flights at an airport in the provincial capital of Nanchang on Saturday morning, according to local meteorological authorities.