A quarter of the world's seaborne trade squeezes through one narrow strait

The Strait of Malacca, running between Malaysia, Singapore and Indonesia, narrows to under 3 kilometres at its tightest point — yet it carries roughly a quarter of the world's maritime trade by value, including around 80% of the crude oil China imports. Over 60,000 vessels pass through it every year. Any serious blockage there would ripple through the world economy within days.

— Wikipedia contributors, Strait of Malacca — Maritime chokepoint