The world’s largest shipping hubs are suffering elevated levels of congestion as containers pile up at seaports from Singapore to Greece’s Piraeus.

Near Singapore on Monday, the backlog was 22% above normal with 53 container ships anchored off the financial and cargo-transit hub, the highest count since Bloomberg News started tracking the data in April.

The pileup is the latest logistical knot in global supply chains, with satellite shipping data allowing for real-time monitoring of port issues globally. 

The container vessel wait immediately off Singapore, which dealt with an unusual surge in COVID-19 cases last week, started Friday and continued over the weekend, topping the previous count of 45 waiting ships recorded on July 21, when Typhoon In-fa roared through Shanghai.

Like all major container hubs, Singapore relies on a delicate logistical ecosystem, where a storm or a COVID-19 outbreak in another port, transit way or transportation sector can ripple widely. Typhoon Kompasu scattered ships out of Hong Kong and Shenzhen over two weeks ago and congestion rates off that port were still 10.4% higher than normal Monday.

Backups were also seen in several other ports in Southeast Asia Monday, with Port Klang in Malaysia reporting congestion rates 14.5% above normal and Tanjung Pelepas at 29.9% more than usual. Jakarta’s container hub of Tanjung Priok was 6.7% above normal, and Manila’s 6.5% higher.

On the other side of the Pacific, the dual ports of Los Angeles and Long Beach kept at least 79 vessels waiting off the coast of southern California early Monday, as America’s busiest import hub continues to work through a backlog around the clock.

President Joe Biden outlined several steps to alleviate global supply chain disruptions in a meeting with the G-20 Sunday, declaring “solving this is going to take all of us — government and private industry, labor unions and research institutions.”

Savannah, America’s fourth-largest port, has dealt with congestion issues for most of 2021 and tied a high of 28 ships waiting to dock last Wednesday.

In Europe, the Greek port of Piraeus saw an April-to-October high of 18 anchored ships waiting on Monday, as a line of vessels destined for the port stretched out into the Aegean Sea. This comes after China’s Cosco Shipping Holdings Co. raised its stake in the port to 67% last week.