A true Olympic effort. The Seine After a century of ban, the Seine is now swimmable again: On July 17, Paris Mayor Anne Hidalgo swam in it after a race to clean up the river in time for the 2024 Olympics.
The massive cleanup took several years and cost about $1.5 billion. One of the most radical changes is a new underground system aimed at capturing rainwater to prevent the river from overflowing during storms and to prevent runoff from the city’s sanitary network into the Seine. Fluidion, a technology monitoring company based in Paris and Los Angeles, is tasked with measuring pollution levels in the Seine every day. If pollution levels remain low during the Olympics, athletes competing in triathlons and other swimming events are expected to swim in the Seine, with public access planned for 2025.
This is not the first attempt to clean up the Seine: in 1990, the then-mayor of Paris and President Jacques Chirac pledged to clean up the river within three years, but the promise was never fulfilled.
