The heaviest fog to affect southwest China's Chongqing Municipality so far this winter has delayed more than 200 flights and led to the cancellation of another 10, affecting about 15,000 passengers.

The fog, which the municipal observatory said reduced average visibility to less than 100 meters in Chongqing, virtually closed Jiangbei International Airport in the morning on Nov. 24, with no departures or arrivals before 11:30 a.m., airport authorities said.

Flights began to resume at midday, but further delays were reported in the afternoon due to the backlog of flights.

At least three international flights, bound for London, Frankfurt and Nagoya, were delayed for an average of four hours, according to the website of Chongqing Airport Group, which is at www.cqa.cn.

Visibility was only five meters in some areas between late Nov. 23 and early Nov. 24, the observatory said. It said the foggy weather, which started on Nov. 23, will persist through Nov. 26.

On Nov. 23, fog delayed about 100 outgoing flights at Jiangbei. Nearly 10,000 passengers were affected.

In Jinan, capital of east China's Shandong Province, heavy fog delayed all 23 departing flights in the morning on Nov. 24, airport authorities said.

Visibility fell below 50 meters in the cities of Heze and Dezhou, according to the provincial meteorological station.