Staff member unload supplies from an unmanned delivery vehicle at a hotel for COVID-19 quarantine in Hefei, east China's Anhui Province, March 22, 2022. Photo:Xinhua

An unmanned intelligent delivery vehicle runs around a hotel for COVID-19 quarantine in Hefei, east China's Anhui Province, March 22, 2022.Photo:Xinhua

An unmanned disinfection device works in Hefei South Railway Station in Hefei, east China's Anhui Province, April 27, 2022.Photo:Xinhua

An unmanned floor-cleaning device works around Hefei South Railway Station in Hefei, east China's Anhui Province, April 27, 2022.Photo:Xinhua

An unmanned floor-cleaning device works in Hefei South Railway Station in Hefei, east China's Anhui Province, April 27, 2022.Photo:Xinhua

An unmanned floor-cleaning device works in Hefei South Railway Station in Hefei, east China's Anhui Province, April 27, 2022.Photo:Xinhua

Photo taken on April 27, 2022 shows unmanned floor-cleaning devices at a tech company in Hefei, east China's Anhui Province.Photo:Xinhua