The Seine River was supposed to be clean, but now it’s too polluted for the Paris Olympics. What happened?

The men’s triathlon was postponed due to potentially dangerous bacteria levels in the Seine. Blame the rain.

Earlier this month, Paris Mayor Anne Hidalgo swam in the Seine River, a sign of the city’s success cleaning up its notoriously dirty waterway ahead of the Olympics. The cleanup effort was more than just symbolic: during the Olympic Games, athletes would swim in the river for several events.