The Olympic men's triathlon faced a setback as it was postponed shortly before its scheduled start on Tuesday due to water quality tests in the River Seine showing high pollution levels.

Despite assurances from Olympic officials that the Seine would be safe for athletes, the men's event was rescheduled to take place 24 hours later, immediately following the women's race on Wednesday. Paris 2024 and World Triathlon released a joint statement attributing the excessive pollution to heavy rainfall in the French capital over the weekend.

Emphasizing the priority of athlete health, the statement was issued following a meeting held at 3:30 am local time (0130 GMT).

“The tests carried out in the Seine today revealed water quality levels that did not provide sufficient guarantees to allow the event to be held.

“Unfortunately, meteorological events beyond our control … can alter water quality and compel us to reschedule the event for health reasons.”

The training sessions in the Seine planned for Sunday and Monday were already called off by the organizers due to high pollution levels resulting from the rain last week.

However, they were optimistic that the pollution would decrease by Tuesday's race, thanks to the sunny weather in Paris this week, which helps in reducing bacteria levels.

French officials have dedicated 1.4 billion euros ($1.5 billion) in the past ten years to improve the cleanliness of the Seine, which includes the development of new water treatment and storage facilities in and around Paris.

However, the city’s underground drainage and sewage systems are still overwhelmed by heavy downpours, resulting in the discharge of untreated effluent into the waterway.

Following an unusually wet spring and early summer, the Seine has consistently failed water quality tests until early July, posing a significant challenge for the organizers of Paris 2024.

The E.Coli bacteria levels, which serve as an indicator of faecal matter, occasionally exceeded authorized limits by a factor of 10.

The triathlon is set to be the inaugural Olympic event held in the river, with marathon swimming following in the second week of the Games.