Traffic runs smoothly near Guomao Bridge on Feb 16 in Beijing's Central Business District (CBD), in contrast to the usual vehicle congestion, one day before Spring Festival. The holiday, also known as Chinese New Year, begins Feb 18 and ends on Feb 24. Each year, millions of people working or studying in Beijing return to their hometowns to celebrate the important holiday, as it's a time for traditional family reunions. The annual 'human migration' leaves the city much less populated. [Photo/IC]

This Jan 4 file photo shows a traffic jam on a road during the evening rush hour. [Photo/cnr.cn]