The Seine River's water quality has fluctuated significantly leading up to the Paris 2024 Olympics, with initial tests showing unsafe levels of E. coli that delayed the men's triathlon. However, by Wednesday, officials confirmed that the water quality had improved sufficiently for both the men's and women's triathlon events to proceed as planned. Heavy rainfall during the opening ceremony over the weekend was linked to the elevated bacteria levels, prompting the cancellation of practice swims. Paris has invested approximately $1.5 billion in infrastructure improvements to enhance the Seine's water quality, a critical part of the city's Olympic legacy. While past rain events have led to rapid recovery of water quality, organizers have kept contingency plans in place should issues arise again. This marks a significant moment, as swimming in the Seine has been prohibited for over a century due to pollution, making the successful hosting of triathlon events a milestone for the city.