People queue outside a walk-in COVID-19 test center in London, Britain, on Sept. 17, 2020. (Photo by Ray Tang/Xinhua)
People queue outside a walk-in COVID-19 test center in London, Britain, on Sept. 17, 2020. (Photo by Ray Tang/Xinhua)
People queue outside a walk-in COVID-19 test center in London, Britain, on Sept. 17, 2020. (Photo by Ray Tang/Xinhua)