After over a month of Covid restrictions in Shanghai, businesses in the United States and Europe report that only about half of their employees are allowed to return to work.

From the southern metropolis of Shenzhen to the northern province of Jilin, mainland China has enforced travel restrictions and stay-at-home orders since March. Covid controls have varying degrees of effectiveness depending on the location.

Lockdowns in Shanghai, China’s southeastern metropolis, began in late March and have been among the most disruptive – to daily life as well as foreign enterprises and supply lines. The city is home to the world’s busiest port and accounts for around 3.8 percent of China’s GDP.

China’s Ministry of Industry and Information Technology stated on Friday that it has dispatched a team to Shanghai. Resumption of activity at 666 significant enterprises in industries like as chips, biopharma, and auto and equipment manufacture should be prioritised, according to the government.

According to Bettina Schoen-Behanzin, the chamber’s vice president and Shanghai chair, a “substantial” number of members of the European Union Chamber of Commerce in China are on the whitelist, particularly in the manufacturing, chemicals, and auto industries.

However, “many enterprises continue to confront labour shortages and logistical difficulties,” she said in a statement to CNBC, estimating that just about 30% of members’ personnel is eligible to return to work owing to the lockdowns.

If a factory is on the list, it can resume operations if workers live on-site and interaction is limited to persons who have valid negative virus tests – a practise known as “closed-loop management” in the area.