(Bloomberg) -- A city in one of China’s steel hubs is being shut down for three days after a single Covid-19 infection was found there. 

Wugang in Henan Province announced a citywide lockdown starting July 11, making it the latest Chinese city to enact strict mobility curbs amid the country’s ongoing Covid flareup. The city of about 300,000, home to Wuyang Iron & Steel Co., is requiring all residents to stay at home unless they are getting tested for Covid, according to a local government statement Monday.

While it may be the first time a Chinese city has been locked down based on one case, the country has a track record of reacting swiftly to just one or a handful of infections. The approach was reinforced after Shanghai’s initial sluggish response to its outbreak led to a crisis that required confining its 25 million residents to their homes for two months to contain the conflagration. 

The moves are part of China’s zero tolerance approach to Covid-19, which is being tested once again with the arrival of sub-variants that have fueled rising caseloads worldwide. New Zealand, which was also once a Covid Zero adherent before joining the rest of the world in living with the virus, famously locked down the whole country last August after finding just one community infection. 

Despite ever more extreme measures aimed at containing the virus -- from testing an infant more than 70 times to locking down Shanghai Disneyland based on one infection -- the evolving pathogen is proving harder than ever to wipe out. Case counts are rising in several regions, and a jump in infections near Shanghai caused some areas to lock down, despite numbers that are well below the city’s spring peak. 

Growing clusters in the eastern province of Anhui led to the highest level of transmission in more than a month. Infections have spilled over into neighboring Jiangsu province, including the commercial hub of Wuxi city. The city shut entertainment venues, suspended dining-in and reduced operating hours for subway and bus services. Most of the infections in Anhui were in Si and Lingbi counties, which have been locked down as authorities carry out mass testing. 

While close to 30 million people nationwide are under some form of movement restrictions now to quell transmission, authorities have so far steered clear of strict lockdowns in key economic regions. There were 347 local Covid cases reported nationwide for July 11. 

©2022 Bloomberg L.P.