Police officers interact with people during a knowledge quiz to celebrate the upcoming Chinese people's police day at the north square of Nanjing South Railway Station in Nanjing, east China's Jiangsu Province, Jan. 7, 2021. China will mark the Chinese people's police day on Jan. 10 as of 2021. (Xinhua/Ji Chunpeng)

SWAT team members conduct a tactic drill to celebrate the upcoming Chinese people's police day at the north square of Nanjing South Railway Station in Nanjing, east China's Jiangsu Province, Jan. 7, 2021. China will mark the Chinese people's police day on Jan. 10 as of 2021. (Xinhua/Ji Chunpeng)

Police officers pose photos with passengers to celebrate the upcoming Chinese people's police day at the waiting hall of Nanjing South Railway Station in Nanjing, east China's Jiangsu Province, Jan. 7, 2021. China will mark the Chinese people's police day on Jan. 10 as of 2021. (Xinhua/Ji Chunpeng)