The Chinese Academy of Sciences estimated that the recent smog across China has affected more than 800 million people, China Central Television reported on Thursday.

A man fishes near a temple beside a river on a heavy hazy day during winter in Beijing's Gaobeidian village, January 30, 2013. [Photo/Agencies]

The Ministry of Environmental Protection said in a report issued on Wednesday that the smog has spread across Northern, Central and Eastern parts of the country, including the provinces of Hebei, Henan, Shandong, Jiangsu, Anhui, Hubei and Hunan.

The air in 10 cities — from Harbin in the north end of the country to Shanghai in the east — was classified as "heavily polluted".

The air quality in Beijing was rated as "very heavily polluted", with the level of PM 2.5 at 310 micrograms per cubic meter, an index that had slightly dropped than before.

PM 2.5 refers to fine airborne particles below 2.5 micrometers that are considered extremely hazardous to people's health as they go deeper into the lungs than larger particles in the air.

Tourists visit the Tiananmen Square on a hazy day in Beijing, Jan 31,2013.[Photo by Xu Jingxing/Asianewsphoto]