A woman wearing a mask walks by a mall on Sunday in Beijing. The city is racing to control the spread of Covid-19 infections, with tight restrictions and mass testing. The number of infections jumped to 21 on Sunday. Photo: VCG

Residents have to scan their health app to get access through security check points at malls and offices. Photo: VCG

The sparely-filled dairy shelves of a supermarket at 11 a.m. on Monday in Beijing. Residents are stocking up on groceries in preparation for a potential lockdown. Photo: Zhang Ruixue/Caixin

Most vegetables were sold out in a supermarket in Chaoyang district around 11 a.m. on Monday. Photo: Zhang Ruixue/Caixin

Residents walk past a meat counter that’s been nearly cleaned out in a supermarket in Chaoyang district at 7 a.m. Monday. Photo: Zhang Ruixue/Caixin

Shoppers gather around the eggs counter at a supermarket in Chaoyang district on Monday. Photo: Zhang Ruixue/Caixin

Shoppers wait in line to pay for their groceries at a supermarket in Tongzhou district of Beijing on Monday. Photo: VCG

A worker carries bags of vegetables to restock a supermarket in Chaoyang district on Monday morning. Local authorities stressed on Sunday that the supplies of daily necessities are sufficient in Beijing. Photo: Li Congxun, Intern Reporter/Caixin

A healthcare worker transfers bags of garbage to a pick-up point in a locked-down community in Beijing’s Panjiayuan subdistrict on Sunday. As part of Covid control measures, the city designated 14 sealed-off management zones and 14 control zones that day. Photo: Jiang Qiming/China News Service, VCG

A resident waits in line with his pet dog near a Covid-19 test site on Monday in Chaoyang district. Starting on Monday, people who live and work in the district are required to take three rounds of tests within the week. Photo: Ding Gang/Caixin

Employees from nearby construction sites head toward a testing site on Monday in Chaoyang district. All offline in-person classes and activities by after-school tutoring insitutions in the district have been suspended on Sunday. Photo: Ding Gang/Caixin

Employees in Beijing’s Sanlitun area, known for its upscale dining and shopping, wait in line to take the nucleic acid test on Monday. Local authorities have assured business owners and staff that there will be compensation for disruption to business operations. Photo: Ding Gang/Caixin

Healthcare workers in protective suits prepare to conduct nucleic acid tests at a Covid-19 test site in Wangjing of Chaoyang district on Monday. Photo: Hou Yu/China News Service, VCG

Residents line up to get tested at a Covid-19 test site at the Olympic Village in Chaoyang district. The local government has expanded locked down areas on Monday. Photo: VCG