People visit the Great Wall in Yanqing district, northwest of Beijing, on Feb11, 2016, despite heavy smog. [Photo/IC]

3. 271 cities suffer from air pollution

Air quality in 271 out of 338 prefecture-level or above cities failed to meet national standards on the Chinese New Year Eve to 6 am the next morning on Feb 8, primarily because of pollution caused by firecrackers. The PM2.5 density in the 338 cities averaged 148 micrograms per cubic meter while the density for PM10 averaged 210 micrograms per cubic meter for these cities. But air condition in Beijing and Shanghai, and some other big metropolis that have partly banned firecrackers improved from last year.