China’s tough new lockdown measures have led to a major backlog of cargo and container ships in front of Shanghai's port.

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With employees unable to go to work, the world’s largest container port is having to manage with significantly fewer staff. 

As Statista's Anna Fleck shows in the chart below, the scale of the problem, using a map of the area on April 28, as provided by FleetMon, an online tracking portal for ships.

In terms of container throughput, Shanghai’s port is the largest in the world. 47 million 20-foot equivalent units (TEUs, unit of measure for container sizes) were handled there last year. To put this into perspective, the largest port in Europe is in Rotterdam, and had only 15.3 million TEUs handled there in that same year. This Statista graphic provides an overview of the world's largest cargo ports.

FleetMon uses ships’ Automatic Identification Systems (AIS) signals to display traffic volume. These are important in shipping for the exchange of navigational data via radio. Every ship over 20m has to transmit an AIS signal. It transmits, among other things, call name, vessel type, GPS position, dimensions and similar data.