Policemen control UAVs (unmanned aerial vehicles) during the launch ceremony of a UAV task force in Nanjing city, capital of East China’s Jiangsu province, July 14, 2015. The Xuanwu bureau of the Nanjing Police have started using UAVs to aid supervision at large-scale events, in emergency responses, to search for suspects, and in rescue missions. (Photo: China News Service/Yang Weibin)