Smog dampens travelers' holiday spirit

As millions of travelers headed home on Wednesday on the last day of the weeklong National Day holiday, many in northern China, including in Beijing and Tianjin, encountered thick smog that cut visibility, hampered traffic and soured their mood.

Beijing has been blanketed by heavy haze since Monday. The smog grew worse by Wednesday, when by 2 pm the concentration of PM2.5 - airborne particulate matter with diameter of 2.5 microns or less that can penetrate the lungs and harm health-had climbed to 313 micrograms per cubic meter, the Beijing Environmental Monitoring Center said.

Unfavorable weather conditions and the burning of straw were considered the major causes of the heavy air pollution, the center said.