Sniffer dog "Lufei" and trainer Liu Huan walk towards inbound mails release area at Changsha supervision center for international mails in Changsha, capital of central China's Hunan Province, Jan. 10, 2020. The sniffer dog "Lufei" at the Changsha Customs has played an important role in detecting prohibited objects and preventing the spread of animal and plant diseases. In the year of 2019, sniffer dog "Lufei" was on duty for 183 times, detecting 249 batches of hazardous materials. (Xinhua/Chen Sihan)