A visitor (1st L) learns about a 5G-based AR (augmented reality) check and maintenance technology during the 2019 Smart China Expo in southwest China's Chongqing Municipality, Aug. 26, 2019. The 2019 Smart China Expo kicked off Monday at the Chongqing International Expo Center. High techs including 5G live broadcast and 5G remote emergency medical aid are among the expo's highlights. (Xinhua/Tang Yi)