A pre-Olympics swimming event, due to take place Sunday in France's Seine River, has been called off due to pollution in the water, World Aquatics said.
The women's 10k race was scheduled for 07:30 a.m. local time (0530 UTC). The men's 10k was arranged for four hours later.
But heavy rains over the past week in Paris have caused sewers to overflow, polluting the Seine, which runs through the French capital.
"Following recent above-average rainfall in Paris, the water quality in the Seine has remained below acceptable standards for safeguarding swimmers' health," the international water sports body wrote in a statement, having analyzed water samples.
"Consequently, World Aquatics, in consultation with public health authorities and event delivery partners, has canceled the Open Water Swimming World Cup planned for this weekend."
Concerns for athletes' health
World Aquatics President Captain Husain Al Musallam said the swimming body was disappointed to cancel the event, but "the health of our athletes must always be our top priority."
"It is clear that further work is needed with Paris 2024 and local authorities to ensure robust contingency plans are in place for next year," Al Musallam continued.
Two other swimming events — a training session Friday and Saturday's women's race — had already been postponed due to water quality issues.
The World Aquatics statement referenced plans by Paris Olympics organizers to improve water quality in the Seine in the leadup to next year's Games.
Paris Olympics organizers and the city's authorities said in a joint statement Sunday that "in recent weeks, water quality in the Seine has regularly reached the levels required for competitions to be held on the dedicated site, demonstrating the significant progress made."
They said water quality will be closely monitored in the coming days in the hope that triathletes can race in the Seine during a test event scheduled on August 17-20.
Their statement said the recent weather had been "exceptional," with the Paris region seeing its heaviest summer rainfalls since 1965.
Paris cleaning up Seine for Olympic Games
In 2018, Paris announced a €1.4 billion ($1.55 billion) cleanup program aimed at making the river clean enough for the Olympics.
The infrastructure projected includes the building of a place to hold rainwater temporarily to prevent inundating the sewage system all at once during heavy downpours.
Paris is due to host the Olympic Games from July 26 to August 11, 2024. The opening ceremony is due to take place on the Seine, instead of inside the Olympic stadium and at least 600,000 people are expected to watch from the banks of the river.
The Seine is the venue for marathon swimming and the swimming leg of the Olympic and Paralympic triathlons.
Paris Mayor Anne Hidalgo also promised that from 2025 the river would be clean enough in three areas for public swimming.
The city introduced a ban on swimming in the Seine in 1923 due to polluted water.
Water pollution a regular cause for concern
Olympic open-water swimming has frequently been hit by pollution concerns.
At the end of the test event in 2019 ahead of the Tokyo Olympics, swimmers protested against the quality of the water in Tokyo Bay.
At the Rio Olympics in 2016, the prospect of swimming in Guanabara Bay, also very polluted, also made headlines.
