China partly shut the world’s third-busiest container port after a worker became infected with the coronavirus disease, threatening to further disrupt global trade, Bloomberg reports.

All inbound and outbound container services at Meishan terminal in Ningbo-Zhoushan port were halted Wednesday until further notice due to a “system disruption,” according to a statement on the port’s electronic data platform.

A container terminal worker at the port tested positive for coronavirus, the eastern Chinese city’s government said in a WeChat statement.

This is the second shutdown of a Chinese port due to an outbreak recently, after the closure of Yantian port in Shenzhen from late May for about a month.

That disrupted already strained international shipping, and an extended closure at Ningbo could be even more damaging, because trade volumes usually rise toward the end of the year as companies ship Christmas and holiday products.

“There may be far-reaching downstream consequences going into Black Friday and holiday shopping seasons” and the next 24 hours will determine whether there is a large outbreak or not, said Josh Brazil, vice president of marketing at project44, a supply-chain intelligence firm.

“One of the few givens in 2021 is endemic delays, and the fact that conditions can change almost overnight.”

In addition to the closed terminal, containers for shipment through the other terminals will likely slow down.

The port will now only accept containers within two days of a ship’s estimated arrival time, according to a statement from shipping and logistics firm CMA CGM SA. All the close contacts of the infected worker have been identified and are in quarantine, according to Ningbo City’s statement.

A port spokesman who declined to give his name said there was no new information when contacted Thursday.

The suspension means there would be a delay in sailings, according to a statement Wednesday from Hapag-Lloyd AG.

The shuttered terminal accounts for about 25% of container cargo through the Ningbo-Zhoushan port, according to a statement from security consultant GardaWorld, which said “the suspension could severely impact cargo handling and shipping.”

The port was the third-busiest globally in terms of container shipments in 2020 and the second busiest in China after Shanghai, according to maritime publication Lloyd’s List.

The discovery of a port worker that tested positive for the virus shows that virus-prevention measures in Ningbo City still have loopholes, the local government said in a statement on its website Thursday, which urged officials to implement quarantines, disinfection and closure of affected areas to prevent the virus’ spread.

Coronavirus infection shuts terminal at Ningbo-Zhoushan port