The sudden collapse of a building damaged three years ago by an Israeli airstrike highlighted another peril of an acute housing shortage in the Gaza Strip.

The waterway, which links the Red Sea to the Gulf of Aden and Indian Ocean, is a busy transit point for crude oil, cars and other manufactured goods.

Five of Israel’s six desalinization plants are offline. Untreated wastewater from Gaza’s destroyed sewage system could be part of the problem, experts warn.