On Nov. 21, about 7,000 passengers were affected as airspace controls continued in eastern China, this time primarily affecting Shanghai, according to sources with Shanghai Airlines.

By 4 p.m., 150 flights from the city's two airports bound for Guangzhou, Xiamen, Shenzhen, Beijing and Dalian had been postponed.

The controls were imposed beginning on Nov. 20 over eastern China, for unspecified reasons.

Passengers whose flights were delayed are eligible for refunds. Those stranded in the Pudong and Hongqiao airports in Shanghai were provided with water and food.

The effect in Guangzhou, where 1,600 passengers were stranded at the Baiyun Airport on Nov. 20, appeared less severe on Nov. 21 and confined to several flights to Shanghai.

It is unknown how long the controls will persist and airport sources advised passengers to adjust their travel plans and follow updated flight schedules.