Dense fog covered Shanghai Monday morning, causing transportation troubles and delaying flights, said the local meteorological station.

The station released a red-light alarm at 6:12 a.m., forecasting heavy fog with visibility of less than 200 meters. At 7:06 a.m. it the heightened alarm level to black-light, forecasting fog with visibility of less than 50 meters in some places, including the Baoshan, Minhang and Jiading suburbs of the city.

At least 40 flights have been delayed at Hongqiao Airport, though flights in and out Pudong Airport were not affected. Major expressways linking Shanghai to other provinces were closed as well.

The fog also affected water transportation. Four water passages in the Songjiang and Minhang districts were closed from 5:30 a.m. to 7:10 a.m.

The fog cleared off gradually near noon. At 9:51 a.m., the station lowered its alarm, and Hongqiao Airport resumed operation at 10:40 a.m..

Dense fog is common in Shanghai at this season, said meteorological experts, noting that it would probably continue Tuesday morning. The city was also blanketed with fog on Friday and Saturday mornings.

(Xinhua News Agency December 14, 2004)