Dense fog hit city suburbs yesterday morning with visibility in Chongming County and Nanhui and Jinshan districts dropping to below 300 meters, the Shanghai Meteorological Bureau said.

The fog caused delays for more than 600 vessels on the Yangtze River, said the Wusong maritime safety administration.

All passenger ferries to local islands were canceled yesterday morning.

Among those affected were nearly 2,000 workers bound for a shipyard factory on Changxing Island. They were delayed until after 1pm when river traffic began to resume, said maritime officer Xing Dafeng.

River traffic had been affected by the bad weather since Sunday.

Fog started blanketing the waters at the mouth of the Yangtze River after 9pm on Sunday and soon forced all passenger and cargo ships to stay at anchor when visibility quickly dropped to below 500 meters.

Shipping traffic had been intermittent since then. Visibility on the waters stayed above 1,000 meters late yesterday afternoon but the maritime authority were still directing many vessels to pull in and out of the local port following their long wait at anchor because of the weather.

Air traffic returned to normal after 6:45am at local airports yesterday, said air controllers after fog had caused delays to 130 flights at Pudong International Airport and 55 others at Hongqiao Airport on Sunday.

The problems were made worse after 36 planes bound for Pudong airport and 14 heading for Hongqiao airport were forced to land at other nearby air terminals on Sunday, because of the fog.

Weather forecasters said there may be more fog this morning.

Meanwhile, a warm air mass from the south will cause temperatures to rise today. The maximum temperature will reach 17 degrees Celsius, and go even higher than 20 degrees tomorrow and on Thursday.

If the warm weather continues to Saturday, Man Liping, a forecaster with the bureau, said, it would mark the earliest arrival of spring in 136 years. It will be sunny to cloudy until Friday, when drizzle will fall in the city, Man said.

(Shanghai Daily February 10, 2009)