Cui Xiaoli

MORE than 30 flights between Shenzhen and the eastern cities of Shanghai and Hangzhou were delayed by 7 p.m. Thursday as air traffic continued to be restricted in East China.

About 10 flights leaving Shenzhen for Shanghai and six for Hangzhou were delayed up to one hour, while 10 Shenzhen-bound flights from Shanghai and seven from Hangzhou were also delayed, according to the Web sites of the airport authorities in the two eastern cities.

A Shenzhen airport source said only a few outbound flights to Shanghai and Hangzhou were delayed for less than one hour by 4 p.m., mostly due to reasons other than airspace control.

However, the airport’s Web site showed that dozens of fights to cities like Shanghai and Tianjin were delayed Thursday afternoon.

More delays are expected as air traffic may be restricted until the weekend, the Shanghai Morning Post reported Thursday.

No official explanation for the restrictions have been offered yet.

Air traffic was restricted over eastern China from Tuesday, primarily affecting Shanghai.

Of the 725 flights that were scheduled to take off by 7 p.m. from Shanghai on Wednesday, more than 120 were delayed and more than 10 were canceled, the Post said, affecting 7,000 passengers.

The restrictions also affected Guangzhou, with more than 100 flights to and from the Baiyun airport delayed Thursday.

On Wednesday, more than 10 flights from Guangzhou to destinations such as Shanghai and Hangzhou were delayed.

Airport sources have advised passengers to adjust their travel plans and follow updated flight schedules.