Danny Ok, the coach of South Korean sailor Cho Wonwoo, has criticised the quality of the water at Guanabara Bay after his athlete fell ill after the Olympic test event in Rio de Janeiro.
Earlier this month, the Brazilian city held test events for a number of different sports, but the water venues have come in for frequent criticism due to the amount of sewage that is spilled into the bay.
The International Olympic Committee has previously insisted that it has no concerns, but Ok has slammed the standard of the water after Cho went to hospital with dehydration, vomiting and dizziness.
Ok is quoted by BBC Sport as saying: "I can't imagine how they can have racing in this area."
Next year's Olympic Games get underway on August 5.