A PLA air defense unit of the Tibet Military Command has recently held a drill at an area, 4,500 meters above the sea level, in Southwest China’s Tibet Autonomous Region. The live-fire drill aimed to improve air defense preparedness in complex weather conditions. (Photo: China News Service/Zhu Jian)

A PLA air defense unit of the Tibet Military Command has recently held a drill at an area, 4,500 meters above the sea level, in Southwest China’s Tibet Autonomous Region. The live-fire drill aimed to improve air defense preparedness in complex weather conditions. (Photo: China News Service/Zhu Jian)

A PLA air defense unit of the Tibet Military Command has recently held a drill at an area, 4,500 meters above the sea level, in Southwest China’s Tibet Autonomous Region. The live-fire drill aimed to improve air defense preparedness in complex weather conditions. (Photo: China News Service/Zhu Jian)

A PLA air defense unit of the Tibet Military Command has recently held a drill at an area, 4,500 meters above the sea level, in Southwest China’s Tibet Autonomous Region. The live-fire drill aimed to improve air defense preparedness in complex weather conditions. (Photo: China News Service/Zhu Jian)

A PLA air defense unit of the Tibet Military Command has recently held a drill at an area, 4,500 meters above the sea level, in Southwest China’s Tibet Autonomous Region. The live-fire drill aimed to improve air defense preparedness in complex weather conditions. (Photo: China News Service/Zhu Jian)

A PLA air defense unit of the Tibet Military Command has recently held a drill at an area, 4,500 meters above the sea level, in Southwest China’s Tibet Autonomous Region. The live-fire drill aimed to improve air defense preparedness in complex weather conditions. (Photo: China News Service/Zhu Jian)

A PLA air defense unit of the Tibet Military Command has recently held a drill at an area, 4,500 meters above the sea level, in Southwest China’s Tibet Autonomous Region. The live-fire drill aimed to improve air defense preparedness in complex weather conditions. (Photo: China News Service/Zhu Jian)

A PLA air defense unit of the Tibet Military Command has recently held a drill at an area, 4,500 meters above the sea level, in Southwest China’s Tibet Autonomous Region. The live-fire drill aimed to improve air defense preparedness in complex weather conditions. (Photo: China News Service/Zhu Jian)

A PLA air defense unit of the Tibet Military Command has recently held a drill at an area, 4,500 meters above the sea level, in Southwest China’s Tibet Autonomous Region. The live-fire drill aimed to improve air defense preparedness in complex weather conditions. (Photo: China News Service/Zhu Jian)