World Triathlon says the men's triathlon at the Paris Olympics will not go ahead as planned today as pollution levels in the Seine River remain too high.
This has left athletes facing more uncertainty.
The race has been postponed to tomorrow, immediately after the women's event.
Organisers previously said they were confident water quality would improve in time for the race after heavy rains last Friday and Saturday dirtied the river.
Should levels of bacteria remain too high by tomorrow morning, both the men's and women's races are likely to be postponed to Friday.
If by Friday the water quality is still not good enough, the swim leg will be scrapped, and athletes will compete in a duathlon instead.
Paris authorities have promised to make the Seine swimmable as a key legacy of the Games and spent 1.4 billion euros ($1.51 billion) on wastewater infrastructure to contain sewage and minimise spillage into the waterway.
Source: Reuters
