China locks down more than 30 million people as COVID-19 spreads rapidly

China this week banned most people from leaving a coronavirus-hit north-eastern province and mobilized military reservists as the fast-spreading stealth Omicron variant BA.2 fuelled a surge in infections.

Chinese authorities have tightened anti-virus controls at ports, raising the risk of trade disruptions after some auto and electronics factories shut down as the government fights the country's worst COVID-19 outbreak since the start of the pandemic two years ago.

Authorities are enforcing a “zero tolerance” strategy that aims to keep the virus out of the country. It has temporarily shut down major cities to find every infected person. Bus service to China's business capital and biggest city Shanghai was suspended.

China's ports link factories that assemble most of the world's smartphones and computers, as well as medical devices, appliances and other goods, with foreign components suppliers and customers. There was no sign of major disruption, but port operators announced restrictions on face-to-face contact with shippers and sailors.

Shenzhen suspended cross-border freight service at the Liantang crossing into Hong Kong, saying that the Man Kam To crossing would be limited to handling fresh and live food to make sure Hong Kong gets adequate supplies.

Shenzhen, a city of 17.5 million people, is home to some of China's biggest companies including Huawei, BYD Auto, Ping An Insurance Co. of China and Tencent Holding, operator of the popular WeChat message system. Taiwanese-owned Foxconn, which assembles Apple's iPhones, has its China base in Shenzhen.

The latest infection surge, blamed on a fast-spreading variant dubbed "stealth omicron," is challenging Beijing's pandemic strategy. All businesses in Shenzhen and Changchun except those that supply food, fuel and other necessities were ordered to close. Bus and subway services were suspended.

Authorities appear to be trying out a "dynamic 'zero COVID' policy" that still aims to keep out the virus but uses "targeted lockdowns" to try to reduce the economic and social cost.