The lockdown will be the most extensive in China since Wuhan, where the virus was first detected in 2019.
China's largest city on Monday began the country's most-extensive lockdown since 2019 when the virus was first detected.
Shanghai will lockdown in two stages, with half of the city restricted for a week from Monday as China's financial capital faces its worst outbreak of COVID-19 in two years.
The Pudong financial district and nearby areas will be locked down from Monday to Friday as mass testing gets underway, the local government said.
In the second phase of the lockdown, the vast downtown area west of the Huangpu River that divides the city will start its own five-day lockdown Friday.
The city of 26 million people managed past outbreaks with limited lockdowns in areas where the virus was spreading.
The two-phase lockdown starting on Monday will be the most extensive since the city of Wuhan was fully restricted when COVID-19 was first detected.
Residents will be required to stay home and deliveries will be left at checkpoints to make sure there is no contact.
Shanghai detected another 3,500 cases of infection on Sunday, though all but 50 were people who tested positive for the coronavirus but were not showing symptoms of COVID-19.
China has reported more than 56,000 confirmed cases nationwide this month, with the surge in the northeastern province of Jilin accounting for most of them.
The country has been employing a zero-tolerance approach to preventing COVID-19.
The new measures being enforced in Shanghai aim to “curb the virus spread, protect people’s life and health, and achieve the dynamic zero-COVID target as soon as possible,” the city’s COVID-19 prevention and control office stated in an announcement on Sunday evening.
China's vaccination rate is around 87% but is lower among older adults who are more likely to become seriously ill if they get the virus.
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