Every foreign airline will be required to maintain only one air route to China and operate no more than one flight a week starting Sunday, the Civil Aviation Administration of China said in a circular on Thursday, in the latest move to cut international passenger flights and curb imported novel coronavirus infections.

Domestic airlines also are asked to retain only one air route with each foreign country and operate no more than one flight a week starting Sunday, according to the circular.

The retained flights should be based on the international flight plan between March 16 and 22 released by the administration on March 12. Airlines should submit their flight plans to the administration for approval in advance, the circular said.

Air route permits and flight schedules of the suspended flights will be preserved for airlines that follow the circular, it said.

Flights to and from China should carry no more than 75 percent of the passengers that they are licensed to carry, the circular said.

The flights could be further slashed in accordance with epidemic development, and airlines should pay close attention, it added.