The self-propelled anti-aircraft artillery (SPAAA) systems concentrate fire on the mock terrorists in the China-Russia joint military exercise ZAPAD/INTERACTION-2021 at a training base of the PLA Army in Qingtongxia City of northwest China's Ningxia Hui Autonomous Region from August 9 to 13, 2021. (eng.chinamil.com.cn/Photo by Wang Weidong)
