A heavy fog that blanketed Shanghai since late Monday has forced the cancellation of flights, highway closures and the suspension of ferry services, Xinhua reported. Shanghai Meteorological Center issued the first fog warning at 9:46 p.m. Monday and upgraded it to a color-coded "red" warning, the highest level at 1:41 a.m. Tuesday. The fog reduced visibility in the city's Pudong and Hongqiao airports to 100 meters and 900 meters respectively. At Pudong, the worst hit area, more than 100 domestic and international flights were delayed and a few had been canceled since Monday night. China Civil Aviation Administration's regulations stipulated that an airport's standard visibility for plane's taking off and landing was 550 meters and 800 meters respectively. All flights returned to normal at 9 a.m. on Tuesday at Pudong airport as the fog dispersed. As of 6 p.m. Tuesday, more than 100 foreign vessels were still awaiting border entry at the mouth of the Yangtze River in Shanghai. Vessels which had planned to sail out were also stranded at the piers. The heavy fog appeared after a warm air mass from the sea encountered cold air in Shanghai. The fog was expected to dissipate in the afternoon, according to the meteorological station.
