China locked down Shenzhen, its tech hub and second biggest port, and imposed severe curbs on Shanghai, its biggest port, as nationwide cases doubled in a day. But what is being called China’s worst outbreak in two years still refers only to 66 new cases registered on Mar. 13 in Shenzhen, a city of 17 million people, and 65 cases in Shanghai, a city of nearly 25 million.
In Shenzhen, all non-essential workers must stay home—which means that the factories making iPhones, semiconductor chips, computers, and other tech products will not function for a…
