Around 21 million people in Chengdu, China, went into lockdown on Thursday as COVID-19 cases increase in numbers and authorities throw attempts at controlling it. 

China is one of the last economies that look to 'flatten the curve' when it comes to COVID-19, still implementing snap shutdowns, mass testing, and prolonged quarantine periods.

Chengdu is the most recent city to announce a shutdown, with a Thursday curfew announced from 6:00 pm onwards to combat the virus, with a set of rules. In each household, only one person can be sent out to buy groceries per day, as long as they'd tested negative in the previous 24 hours, according to a notice.

Read next: Azvudine, China's COVID-19 pill, has been delivered to various regions

Every resident will be tested for COVID-19 between Thursday and Sunday in the city, as they're urged not to leave the city unless "absolutely necessary." 

"The current state of epidemic control is abnormal, complex, and grim," the announcement said, adding that the measures aimed to "decisively arrest the spread of the outbreak and guarantee the health of all citizens".      

On Thursday, Chengdu recorded 157 new local infections, 51 of which were asymptomatic, according to local authorities in a separate notice.

Volvo, a Swedish car company, said it had to close down its plant in Chengdu, which employs almost 3,000 people.

Chengdu is not the only Chinese city enduring lockdown measures: Xining in Qinghai province is mass testing its residents, urging inhabitants in urban areas to work remotely for 3 days.

Shenzhen's government also announced that new virus restrictions will be implemented Thursday evening in its Nanshan district, where major technology companies are located, such as Tencent and ZTE. Bars, cinemas, karaoke clubs, and other entertainment venues will be closing down, and residents will have to provide a recent negative COVID-19 test to make it home.

Read more: Cities in Eastern China tighten Covid curbs as new clusters erupt

Two weeks ago, the General Administration of Customs announced that China is moving further to ease anti-COVID-19 restrictions on international arrivals, scrapping requirements for visitors to report information regarding nucleic acid test results, their infection status, and vaccination dates.