People work at the National Exhibition and Convention Center in east China's Shanghai, April 6, 2022. Shanghai is converting the National Exhibition and Convention Center (NECC) into a makeshift hospital with a planned capacity of 40,000 beds. Upon completion, it is expected to act as the biggest such hospital for those testing positive for COVID-19 in the metropolis. (Xinhua/Ding Ting)

People work at the National Exhibition and Convention Center in east China's Shanghai, April 6, 2022. Shanghai is converting the National Exhibition and Convention Center (NECC) into a makeshift hospital with a planned capacity of 40,000 beds. Upon completion, it is expected to act as the biggest such hospital for those testing positive for COVID-19 in the metropolis. (Xinhua/Ding Ting)

People work at the National Exhibition and Convention Center in east China's Shanghai, April 6, 2022. Shanghai is converting the National Exhibition and Convention Center (NECC) into a makeshift hospital with a planned capacity of 40,000 beds. Upon completion, it is expected to act as the biggest such hospital for those testing positive for COVID-19 in the metropolis. (Xinhua/Ding Ting)

People work at the National Exhibition and Convention Center in east China's Shanghai, April 6, 2022. Shanghai is converting the National Exhibition and Convention Center (NECC) into a makeshift hospital with a planned capacity of 40,000 beds. Upon completion, it is expected to act as the biggest such hospital for those testing positive for COVID-19 in the metropolis. (Xinhua/Ding Ting)

People work at the National Exhibition and Convention Center in east China's Shanghai, April 6, 2022. Shanghai is converting the National Exhibition and Convention Center (NECC) into a makeshift hospital with a planned capacity of 40,000 beds. Upon completion, it is expected to act as the biggest such hospital for those testing positive for COVID-19 in the metropolis. (Xinhua/Ding Ting)

People work at the National Exhibition and Convention Center in east China's Shanghai, April 6, 2022. Shanghai is converting the National Exhibition and Convention Center (NECC) into a makeshift hospital with a planned capacity of 40,000 beds. Upon completion, it is expected to act as the biggest such hospital for those testing positive for COVID-19 in the metropolis. (Xinhua/Ding Ting)

People work at the National Exhibition and Convention Center in east China's Shanghai, April 6, 2022. Shanghai is converting the National Exhibition and Convention Center (NECC) into a makeshift hospital with a planned capacity of 40,000 beds. Upon completion, it is expected to act as the biggest such hospital for those testing positive for COVID-19 in the metropolis. (Xinhua/Ding Ting)

People work at the National Exhibition and Convention Center in east China's Shanghai, April 6, 2022. Shanghai is converting the National Exhibition and Convention Center (NECC) into a makeshift hospital with a planned capacity of 40,000 beds. Upon completion, it is expected to act as the biggest such hospital for those testing positive for COVID-19 in the metropolis. (Xinhua/Ding Ting)

People work at the National Exhibition and Convention Center in east China's Shanghai, April 6, 2022. Shanghai is converting the National Exhibition and Convention Center (NECC) into a makeshift hospital with a planned capacity of 40,000 beds. Upon completion, it is expected to act as the biggest such hospital for those testing positive for COVID-19 in the metropolis. (Xinhua/Ding Ting)

People work at the National Exhibition and Convention Center in east China's Shanghai, April 6, 2022. Shanghai is converting the National Exhibition and Convention Center (NECC) into a makeshift hospital with a planned capacity of 40,000 beds. Upon completion, it is expected to act as the biggest such hospital for those testing positive for COVID-19 in the metropolis. (Xinhua/Ding Ting)