The global shipping industry, already exhausted by pandemic shocks that are adding to inflation pressures and delivery delays, faces the biggest test of its stamina yet.

When one of China’s busiest ports announced it wouldn’t accept new export containers in late-May because of a COVID-19 outbreak, it was supposed to be up and running again in a few days. But as the partial shutdown drags on, it’s further snarling trade routes and lifting record freight prices even higher.

Yantian Port now says it will be back to normal by the end of June, but just as it took several weeks for ship schedules and supply chains to recover from the vessel blocking the Suez Canal in March, it may take months for the cargo backlog in southern China to clear while the fallout ripples to ports worldwide.