Hong Kong citizens welcome a nucleic testing support team from the Chinese mainland on their arrival in Hong Kong, south China, Aug. 21, 2020. (Xinhua/Li Gang)

Members of a nucleic testing support team from the Chinese mainland arrive at the Metropark Hotel Kowloon in Hong Kong, south China, Aug. 28, 2020. (Xinhua/Wang Shen)

Representatives of a nucleic testing support team from the Chinese mainland pose for a photo during a welcome symposium at Metropark Hotel Kowloon in Hong Kong, south China, Sept. 4, 2020. (Xinhua/Wang Shen)

Photo taken on Aug. 26, 2020 shows the "Fire Eye Laboratory" in Hong Kong, south China. (Xinhua/Li Gang)

Members of a nucleic testing support team from the Chinese mainland arrive at the Metropark Hotel Kowloon in Hong Kong, south China, Aug. 28, 2020. (Xinhua/Wang Shen)

People visit the "Fire Eye Laboratory" in Hong Kong, south China, Aug. 26, 2020. (Xinhua/Li Gang)

People walk past a poster of the Universal Community Testing Program in Hong Kong, south China, Sept. 1, 2020. (Xinhua/Li Gang)

Hong Kong citizens pose for a photo with members of the first group of nucleic testing professionals from the Chinese mainland in Hong Kong, south China, Aug. 2, 2020. (Xinhua/Li Gang)