People wait in line for nucleic acid samples in Shanghai, China, March 12, 2022.People wait in line for nucleic acid samples in Shanghai, China, March 12, 2022.

Major cities in mainland China are rushing to limit business activity as the country faces its worst Covid-19 outbreak since the country banned the disease in 2020.

Shenzhen, the biggest city in the manufacturing hub of Guangdong province, told businesses not involved with essential public services to suspend production or have employees work from home for a week starting Monday. Apple supplier Foxconn did not respond to a CNBC request for comment.

The city has shut public transportation and begun a third round of testing. Shenzhen has reported more than 400 confirmed cases.

In comparison to other countries, the numbers and case counts in China pale. The rapid increase in cases in the last few days has local authorities rushing to control the outbreak as China seeks to maintain its zero- Covid strategy.

The coastal metropolis home to many foreign businesses and financial firms in China has reverted schools to online classes. Residents can't leave until the results of the mass testing come back negative.

The city told residents not to leave unless absolutely necessary. There have been more than 600 confirmed cases.

Jilin province in northern China reported an overnight surge of over 1,000 new locally transmitted coronaviruses cases, for a total of more than 2,900 cases this month as of Sunday.

As of Sunday, mainland China reported 1,437 new confirmed cases, with 100 of them attributed to travelers from overseas. That is the most since March 2020. There have been no new deaths reported.

There has been a resurgence of Covid cases in Hong Kong in the last few weeks. According to Our World in Data, the region has the highest number of new Covid-related deaths per million people.

The highly transmissible omicron variant has spread to the mainland.

The capital city of Beijing said Sunday it identified six sources of transmission for the latest handful of municipal cases, mostly reported around the downtown and eastern parts of the city. People returning to Beijing are not allowed to attend gatherings for seven days.

The capital has one of the strictest Covid control policies in the country. Travelers need to take a negative Covid test 48 hours before entering Beijing and another 72 hours after arriving. They are not allowed into the city if their 14-day travel history shows they visited a locale with a confirmed case.

In February 2020 mainland China shut down most of the country to control the outbreak after the emergence of Covid-19. Domestically, the virus came under control within a few weeks, but Covid spread overseas in a global epidemic.

South Korea and Germany have the highest new case counts at over five million and over four million, respectively. As of Monday morning Beijing time, the U.S. has recorded more deaths than any other country.

The policy has been in place for the last two years. Domestic tourism and services businesses have been affected by the travel restrictions.

An annual parliamentary meeting that wrapped up Friday gave no signs that the central government plans to loosen its Covid control policy.

The country should follow the zero-covid policy and take other measures to prevent a large-scale virus resurgence, according to the vice premier.

Her remarks were published by state media and she called for preparation for a top meeting of the Communist Party later this year. At the meeting, the Chinese President is expected to get a third term.

The strategy did not work in the first place, so abandoning it could be seen as acknowledging that.

The next 12 months are a crucial time for the one-in-a-decade leadership change, which is pushing top leaders to stick to the status quo in order to avoid making policy mistakes.

China's Center for Disease Control and Prevention published a study in November that said shifting to the coexistence strategy of other countries would likely result in hundreds of thousands of new daily cases.

Lu said that the economic costs of the zero- Covid strategy are rising.

He said that more individuals are feeling the pinch, becoming worn out, unemployed or underemployed, and have drained their savings to a level at which they have.