Photo credit: Air China

Air China service to Pyongyang will be canceled on April 17.

“Air China will no longer be servicing the Pyongyang to Beijing air route after April 17. Up until now, Air China has been the only carrier outside of Air Koryo to service North Korea.”

Air China had been operating three round-trip flights a week. In recent months, this service has been based more on demand rather than posted schedules.

North Korea sells millions of tons of coal to China every year - accounting for about a third of the petulant country's official exports in 2015.

Sources:

https://media.8ch.net/file_store/0fe0eb4e5414a87c0a48de0f0e0798680c6467183c5bde748ac267b585456a09.png

http://money.cnn.com/2017/04/14/news/north-korea-air-china-pyongyang/index.html