BEIJING, Jan. 16 (Xinhua) -- A cold snap starting Tuesday is expected to disperse the smog that has lasted for several days in northern China, the country's meteorological authorities said Tuesday.

From Tuesday to Thursday, a cold front will sweep parts of Xinjiang, Inner Mongolia and the northeast to disperse smog, the National Meteorological Center (NMC) said in a statement.

These areas will see temperatures drop by 4 to 6 degrees Celsius accompanied by heavy wind, said the NMC.

Air conditions in central and southern areas of northern China as well as western and central parts of the Yellow and Huaihe river basins will improve from Wednesday afternoon.

Starting last Saturday, mild to moderate smog has swept central and southern parts of northern China as well as western and northern areas of the Yellow and Huaihe river basins.

Beijing issued an orange alert last Friday for air pollution, advising children and the elderly to stay indoors and for certain construction activities to be suspended and heavy vehicles to be removed from the road.?