SEOUL/SINGAPORE — Congestion at Singapore's container port is at its worst since the Covid-19 pandemic, a sign of how prolonged vessel rerouting to avoid Red Sea attacks has disrupted global ocean shipping with bottlenecks also appearing in other Asian and European ports.

Retailers, manufacturers and other industries that rely on massive box ships are again battling surging rates, port backups and shortages of empty containers, even as many consumer-oriented firms look to build inventories heading into the peak year-end shopping season.