Air traffic in Shenzhen was brought almost to a halt by thick fog Thursday morning, with more than 150 flights delayed and 16 canceled.

According to a source at the airport, flights were delayed until midday.

“The airport was shrouded in fog even at 11 a.m. and many passengers just had to wait in the lounges,” said the source.

The situation had returned to normal by noon.

The longest delay was about four hours. Flights were canceled to Shanghai, Nanchang, Beijing, Hangzhou and Sanya.

However, expressways around Shenzhen remained open in spite of the fog, which reduced visibility to 200 meters with relative humidity of 99 percent.

A Shekou ferry terminal spokesman, Mr. Liu, said the fog had resulted in the cancellation of only three ferries from Shenzhen to Zhuhai.

He said that since there were not so many passengers, those who were delayed eventually left without much of a problem.

Shenzhen experienced the foggiest day for more than a decade Thursday, with visibility down to only 200 meters and relative humidity of 99 percent.

According to a weather observatory source, 99-percent relative humidity meant that the moisture content in the air was almost at saturation point and high humidity usually induced fog with moisture accumulating on windows and other places exposed to the air. Normally, relative humidity ranging from 50 to 80 percent is considered comfortable.

According to meteorological observatory records, the last time visibility was reduced to 200 meters in Shenzhen was in 1992.

(Shenzhen Daily February 26, 2005)