The heavy haze and fog descended on most parts of North China, western Yellow-Huaihe valley and Shaanxi, on Oct. 9, 2014. These areas saw heavy pollution weather. Average concentration of PM2.5 in Beijing, Tianjin and Hebei was about 250 micrograms per cubic meter, even over 400 micrograms per cubic meter in some periods.

　　Actual condition of haze from 5 a.m. of Oct.9 to 5 a.m. of Oct.10.