A member of a mainland nucleic acid test support team thumbs up to Hong Kong residents on a bus in Hong Kong, south China, Sept. 16, 2020. (Xinhua/Wang Shen)

Secretary for Food and Health of the Hong Kong Special Administrative Region (HKSAR) government Sophia Chan (1st R, front) and Secretary for Constitutional and Mainland Affairs of the HKSAR government Erick Tsang Kwok-wai (2nd R, front) see off members of mainland nucleic acid test support teams at their hotel in Hong Kong, south China, Sept. 16, 2020. (Xinhua)

Hong Kong residents see off members of mainland nucleic acid test support teams at their hotel in Hong Kong, south China, Sept. 16, 2020. (Xinhua/Wang Shen)

Staff members of a hotel wave goodbye to members of mainland nucleic acid test support teams in Hong Kong, south China, Sept. 16, 2020. (Xinhua/Wang Shen)

A Hong Kong resident thumbs up to members of mainland nucleic acid test support teams at their hotel in Hong Kong, south China, Sept. 16, 2020. (Xinhua/Wang Shen)

Hong Kong residents see off members of mainland nucleic acid test support teams at their hotel in Hong Kong, south China, Sept. 16, 2020. (Xinhua/Wang Shen)

Hong Kong residents see off members of mainland nucleic acid test support teams at their hotel in Hong Kong, south China, Sept. 16, 2020. (Xinhua/Wang Shen)

A Hong Kong resident thumbs up to members of mainland nucleic acid test support teams at their hotel in Hong Kong, south China, Sept. 16, 2020. (Xinhua/Wang Shen)