Shanghai’s COVID-19 outbreak has been largely contained and is now “under effective control”, authorities said on Friday. The situation in Shanghai was dubbed the worst coronavirus outbreak in China.

China’s “zero-COVID strategy” resulted in more than 25 million people being under government-mandated quarantine for nearly a month. The economic costs of the Shanghai lockdown were also seen around the world as the economic hub went silent.

Also Read: Beijing relaxes quarantine rules as Hong Kong reopens beaches

Shanghai’s vice mayor Wu Qing announced on Friday that fresh infections of COVID-19 in the city were experiencing a “continuous downward trend” since April 22, Reuters reported.

“Currently, our city’s epidemic prevention and control situation is steadily improving, and the epidemic has come under effective control”, the vice mayor said in a press conference.

However, officials warned that there may be a chance of another COVID-19 wave coming back to the city even if cases had been “effectively curbed” for now. The city would continue to stick with the “dynamic clearance” strategy for now.

“We cannot relax, we cannot slack off: persistence is victory,” he said, echoing comments at a meeting of the standing committee of the ruling Communist Party’s politburo late on Thursday, according to reports from Reuters.

China’s national capital Beijing also seems to be slowly moving towards eased COVID regulations. The city has mandated all passengers on international flights to quarantine at a hotel for 10 days, followed by another week of home isolation.

Also Read: Work from home returns to Beijing as subway stations shut amid Covid surge

Previous rules required 21 days of isolation, at least 14 of them at a hotel, followed by seven days of regular health reporting, according to reports from Associated Press.

Still, the capital is taking no chances and on Wednesday closed 60 subway stations, more than 10% of its vast system, to reduce the possibility of the virus spreading. Restaurants and bars are limited to takeout, gyms are closed and classes are suspended for at least another week.