Shanghai weather bureau issued this morning yellow alert for fog, which means the visibility in some area of the city is no more than 500 meters.
The third worst warning is expected to be dismissed by mid-afternoon, said the weather bureau about 8 AM.
Dense fog has urged closure of several ferries over the Huangpu River and high-ways, while city's two airports, Hongqiao and Pudong, are in normal operation.
Road accidents have been reported since 8 AM on the high-way connecting Shanghai and Hangzhou City.
Local traffic authority warned drivers to control speed and keep proper distance in foggy weather.
Meanwhile, a cold front arrived last night, blowing away rainy clouds that had dominated the city for several days.
Mercury is expected to climb back to 10 degrees Celsius during daytime today from yesterday's 8 degrees, said the city's weather bureau.
Drizzle is in forecast tomorrow.
(Shanghai Daily January 18, 2007)