A helicopter attached to an aviation search and rescue regiment of the air force under the PLA Western Theater Command patrols the snow-covered border area in western China on September 23, 2018. (Photos: eng.chinamil.com.cn)

A helicopter attached to an aviation search and rescue regiment of the air force under the PLA Western Theater Command patrols the snow-covered border area in western China on September 23, 2018.

A helicopter attached to an aviation search and rescue regiment of the air force under the PLA Western Theater Command patrols the snow-covered border area in western China on September 23, 2018.