Competitors have praised the condition of the Guanabara Bay in the final 2016 Rio Olympics sailing test event here.
More than 300 sailors from 52 countries and regions took part in the regatta on Saturday and which will run until next Saturday, reported Xinhua news agency.
The iconic venue resembled a postcard image as competition began under a cloudless sky against a backdrop of Sugarloaf mountain and the Christ the Redeemer statue.
The event comes amid media reports that untreated sewage and rubbish in the bay could pose a health risk to athletes.
"The water is excellent. There is no reason to complain about anything and that's coming from somebody who usually complains a lot. The weather helped too. It's been a while since it rained," said Brazilian sailor Ricardo Winicki.
Rio's city government has deployed 10 eco-boats to scoop garbage from the water's surface before and during the event. Large nets have also been placed in strategic parts of the bay to prevent the flow of rubbish from connecting rivers.
United States coach Jay Glaser said the conditions were no more difficult than those encountered in other parts of the world.
"In San Diego, when you sail, you get seaweed. In Newport, Rhode Island, it's grass, in Queensland, Australia, you're worried about box jelly fish. This is a great place to sail, super-scenic, really challenging," Glaser said.
France's Jonathan Lobert, winner of the Finn class bronze medal at the 2012 London Games, also lavished praise on the bay.
"It's very nice for the sport to be in the heart of the Olympic city because sailing is usually a little bit away," he said.
Organisers say the sailing courses to be used for the Olympics will be in deep water where open sea currents ensure constant high water quality.
