Paris, France - Olympic organizers canceled part of the triathlon training in the River Seine planned for Saturday, saying heavy rain was likely to have made the waterway too polluted to swim in.

Only the running and cycling elements of the triathlon mixed relay training will take place, Paris 2024 organizers announced in a statement.

Training was scrapped due to "the heavy rain over the last two nights, which have been particularly intense upstream of Paris, and the expected drop in water quality as a result."

French authorities have invested 1.4 billion euros ($1.5 billion) over the last decade to clean up the Seine, including in major new water treatment and storage facilities in and around Paris.

But heavy downpours still overwhelm the city's underground drains and sewage system, leading to untreated effluent being released into the waterway.

The on-off water cleanliness issue has been a major talking point at the Paris Games, with pollution forcing a 24-hour postponement of the men's triathlon on Tuesday.

Both the men and the women finally dived into the Seine on Wednesday after the pollution levels were "assessed as compliant."

The weather during the Paris Games has been extremely temperamental, veering from heatwave to deluge, notably during the opening ceremony which was marred by torrential rain.