Over 20,000 bankers and traders in Shanghai have reportedly been living at their offices for the past month, due to harsh restrictions imposed to battle China’s worst-ever COVID outbreak.

The city has recorded 540,000 cases since the beginning of March, which is when the first COVID cases of the current wave were detected. A citywide lockdown, imposed in the first week of April to stymie transmission of the virus, has kept residents confined to their homes, causing food shortages and public frustration.

But before authorities imposed the stay-at-home orders, financial institutions, like the Industrial and Commercial Bank of China and the Shanghai Stock Exchange, asked some employees to move to the office in order to keep financial services running smoothly during Shanghai’s lockdown, now in its fifth week. 

The bankers have been sleeping on foldable beds, eating in the office cafeteria, and cleaning themselves in office restrooms. They may have finally had enough.

On Tuesday, the Asia Securities Industry and Financial Markets Association (ASIFMA), a group representing major banks and financial institutions, asked Shanghai authorities to allow banks to rotate their staff, giving workers a chance to go home, according to Reuters.

“There are hundreds of employees from financial services firms who have been trapped in their office buildings for several weeks and separated from their families,” ASIFMA explained in the letter, as reviewed by Reuters. According to the letter, Shanghai regulators require banks to maintain a minimum staff presence on location to maintain trading operations, which is why thousands of bankers have been camping out in the city’s skyscrapers.

ASIFMA did not immediately respond to a request for comment.

But bankers and traders are not the only people living at work during Shanghai’s lockdown. Shanghai’s port—the world’s largest—has kept some operations running though a “closed-loop system,” where workers live on-site. City authorities also allowed some factories like Tesla’s Shanghai Gigafactory to resume production by implementing a similar system.

Yet those stuck at work might be able to return home soon, as Shanghai may be turning a corner in its COVID outbreak. The city recorded just over 10,600 cases over the past 24 hours, a 21.7% decrease from the day before. Shanghai officials are now working on ways to restart manufacturing and reopen public transport and downtown retail, according to the South China Morning Post.

Yet other Chinese cities are scrambling to control their case numbers and avoid the disruption and public anger seen in Shanghai. On Tuesday, Beijing ordered nearly all of its 21 million residents to undergo three rounds of COVID tests as it tries to control cases and avoid a lockdown. China’s capital city has reported 160 cases since last Friday.

Authorities in the tech hub of Hangzhou also ordered a round of mass testing on Thursday. The cities of Yiwu—which manufactures 80% of China’s Christmas-related exports—and Qinhuangdao—a major port for Chinese coal—have also been subject to some COVID-related lockdowns.