Open water swimming training in the River Seine was cancelled today following the heavy rainfall ©World Aquatics

An open water swimming test event for next year’s Olympics in Paris has been postponed after heavy rain caused pollution in the River Seine.

World Aquatics announced the postponement of its Open Water Swimming World Cup meeting in the French capital after ruling that the water quality in the river is "still below acceptable standards for safeguarding swimmers’ health".

A training session, which was due to be held today, has been cancelled while the women’s 10 kilometres race has been moved from tomorrow to Sunday (August 7) when the men’s 10km event is also set to be staged.

World Aquatics said it would continue to monitor the water quality before giving another update at 5am local time tomorrow.

The event is the fourth stop on the Open Water Swimming World Cup after stages in Egypt, Italy and Portugal.

It is also set to act as a test event for Paris 2024 as the River Seine is due to host open water swimming and triathlon competitions during the Games.

"This should allow us to see if the aquatic operations that we are going to organise on the Seine work with, for example the installation of the starting pontoon," said Brigitte Légaré, senior sport cluster manager at Paris 2024.

"This also allows us to test aspects related to water quality for next year."

Organisers are set to continue to monitor the water quality of the River Seine before a decision is made on the staging of the Open Water Swimming World Cup meet ©Getty Images
Organisers are set to continue to monitor the water quality of the River Seine before a decision is made on the staging of the Open Water Swimming World Cup meet ©Getty Images

Pierre-Antoine Molina, secretary general for public policies at Île-de-France, told French newpaper Le Parisien that Paris had experienced an "exceptional rain episode".

"We made 42 measurements between June 6 and July 19 and we have seen an improvement in water quality," said Molina.

"Between July 20 and August 2, 104 millimetres of water fell on Paris.

"This had not happened for at least 20 years and it is four times more than the average of the last 20 years."

Christophe Ribet, chief of staff to Pierre Rabadan, deputy mayor of Paris in charge of sport, insisted that he remained "very confident" for Paris 2024.

This month is also set to see World Triathlon stage a test event from August 17 to 20.

Public swimming in the Seine has been a key legacy ambition of Paris' hosting of the Olympic and Paralympic Games.

Authorities had banned swimming in the river in 1923 because of high levels of pollution, a problem stretching back to the 16th century when the bodies of those killed in religious wars between Protestants and Catholics were thrown into the water.

France has spent around €1.4 billion (£1.2 billion/$1.5 billion) in its attempts to clean up the River Seine.