The men's triathlon at the Paris Olympics will not go ahead as planned on Tuesday as pollution levels in the Seine remain too high, World Triathlon said in a statement, dealing a blow to organisers and leaving athletes facing more uncertainty.
The race was postponed to Wednesday at 10:45 a.m. (0845 GMT), immediately after the women's event.
Should levels of bacteria remain too high by Wednesday morning, both the men's and women's races are likely to be postponed to Friday.
Eleven gold medals are up for grabs on Tuesday, including women's rugby sevens, table tennis mixed doubles and a series of swimming races.
The US, led by Biles, are heavy favourites to win gold in the artistic gymnastics team final.
The last day of action in a hugely successful rugby sevens programme features the semis and finals of the women's event.
Reigning champion Agbegnenou of France defends her title in front of a partisan home crowd in the under-63kg division.
In the men's under-81kg category, three-times world champion Tato Grigalashvili of Georgia is the clear favourite and could take on Japan's reigning Olympic champion Takanori Nagase.
And we're not just talking about the fights for medals. A heatwave is hitting France and the temperature is due to rise to 35 degrees Celsius (95°F) in Paris and 37 degrees in Chateauroux, where the shooting competitions are taking place.
In Marseille, sailors donned ice vests to beat the searing Mediterranean heat.
Daiki Hashimoto turned heartache into unimaginable joy as he overcame a fall from the pommel horse to power Japan to the gold medal and edge out China in a pulsating gymnastics men's team final on Monday. That put Japan top of the medal table with six golds, ahead of hosts France and China who have five.
After losing to Novak Djokovic in singles on Monday, 14-times French Open champion Rafa Nadal now has only the doubles competition left to add to his two Olympic gold medals.
Partnering Carlos Alcaraz, they face a Dutch team on Tuesday in the second round.