The Seine, which flows through the heart of Paris, was sick for 100 years. For the first time since 1923, people were allowed to swim in the Seine. This is after an extensive clean-up of the river. The Yamuna is similarly polluted in Delhi.

Just one day after opening the Seine River to swimming for the first time in more than a century, French officials shut down the river due to concerns about pollution following heavy rainfall. Swimming in the Seine has largely been illegal since 1923 due to pollution and other safety risks.

First, France cleaned the polluted river so that Olympians could swim there. Now, a year later, it is opening three sites for locals to plunge in.