China yesterday placed all 17 million residents in one of its biggest cities under lockdown, as virus cases doubled nationwide to nearly 3,400 and anxiety mounted over the resilience of its zero-Covid approach in the face of the worst outbreak in two years.

The southern tech-hub of Shenzhen told all residents to stay at home as the city struggles to eradicate an Omicron flare-up linked to neighbouring virus-ravaged Hong Kong. The lockdown and a suspension of public transport will last until March 20, a city government notice said, adding that it would launch three rounds of mass testing.
The move extends an earlier lockdown imposed on the citys central business district.
Shenzhen reported 66 new infections yesterday a fraction of the 32,430 confirmed the same day in Hong Kong.
The surge in infections across China has also prompted authorities to close schools in Shanghai and lockdown multiple north-eastern cities, as 18 provinces battle clusters of the Omicron and Delta variants.
China, where the virus was first detected in late 2019, has maintained a strict zero-Covid policy enforced with swift lockdowns, travel restrictions, and mass testing when clusters have emerged.
But the latest flare-up, driven by the highly transmissible Omicron variant and a spike in asymptomatic cases, is testing that approach.
Shanghai has so far been spared a citywide order to stay home, but individual housing compounds were being locked down as the megacity ramped up efforts to contain infections and test suspected close contacts.
Some people in Shanghai housing compounds that have been locked down were told by authorities that the restrictions will last two days. Some schools, businesses, restaurants, and malls have also been closed over close-contact fears.
Authorities also said yesterday that people cannot leave or enter Shanghai without a negative test taken in the past 48 hours. Long lines were seen outside hospitals as people rushed to get tested.
Shenzhen residents told AFP earlier yesterday that they were nervous about the renewed outbreak and draconian measures that may be used to tackle it. Its the worst since 2020, a resident, surnamed Zhang, said.
The city, which has a large population of migrant workers, shares a land border crossing with Hong Kong where the caseload over recent weeks has soared, alarming officials in Beijing.
Hong Kong currently has one of the worlds highest death rates from the virus, as the Omicron variant cuts through its elderly population among whom vaccine hesitancy proliferates.
As cases rise, Chinas National Health Commission announced on Friday that it would make rapid antigen tests available for citizens to buy online or from clinics for self-testing.
Although nucleic acid tests will continue to be the main method of testing, the move suggests China may be anticipating that official efforts will not be able to contain the virus.
