Dotting the sea off Chinese ports are 477 bulk cargo ships waiting to deliver resources from metal ore to grain into the country.

Queues of vessels carrying raw materials have jumped after Shanghai initiated a city-wide lockdown at the end of last month to combat COVID-19. More than two weeks on, the congestion has expanded to nearby Ningbo-Zhoushan as ship-owners desperately divert ships to other ports in the country to avoid the trucker shortage and warehouse closures in Shanghai. 

There were 222 bulkers waiting off Shanghai as of April 11, 15% higher than a month earlier, according to Bloomberg shipping data. At Ningbo-Zhoushan there were 134 carriers, 0.8% higher than last month, while further north, the combined ports of Rizhao, Dongjiakou and Qingdao saw a 33% increase to 121 vessels.

Adding to the snarl, there were 197 container ships either loading or waiting to load in Shanghai’s combined anchorage with Ningbo, a 17% increase from a month ago.

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A shortage of port workers at Shanghai is slowing the delivery of documentation needed for ships to unload cargoes, according to ship owners and traders. Meanwhile, vessels carrying metals like copper and iron ore are left stranded offshore as trucks are unable to send goods from the port to processing mills, they said.

Some of that congestion is rippling out to other ports, with ships being diverted further north to ports in Qingdao and Tianjin where trucking services haven’t been as impacted, the people said. At Tianjin, there were 54 ships waiting on April 11, a 29% rise in a month.

Congestion was lower in Hebei and Liaoning provinces, where trucking has also been hampered by compulsory mass testing of truckers and workers in March and April. Ship queues were 36% lower than last month at Liaoning’s Dalian port and 35% lower in Hebei’s Tangshan.