On Dec. 28, at least eight flights were diverted from landing at the Pudong International Airport in Shanghai because of heavy fog.

A spokesman with China Eastern Airlines said clouds were hovering low over the Pudong airport and visibility was poor. Six of the air carrier's flights were forced to land at other airports.

A source from Shanghai Airlines said two of the company's flights were also diverted. One from Wuhan, a city in central China's Hubei Province, had to land at Hongqiao Airport. Another flight from Shenyang, in Liaoning Province, was diverted to Wenzhou, a city close to Shanghai.

Landing and take-offs at the Hongqiao Airport, also in Shanghai, were still on schedule.