A woman stands with a sign that reads "I don't want only postcards" on Botafogo beach, located in Guanabara Bay, during a protest in Rio de Janeiro, June 6, 2015. [Photo/Agencies]

LAUSANNE - The International Olympic Committee (IOC) remains concerned about water pollution at the Rio 2016 Olympic sailing venue, the organization's president Thomas Bach said on Monday.

Guanabara Bay remains littered with trash and untreated sewage despite a government pledge to reduce 80% of waste flowing into its waters.

"We can see significant progress, at the same time we have asked the organizing committee to convey our concerns with regard to the issues of the water quality we are still facing in Rio," Bach told media.

"The IOC executive board is watching this situation very closely and we are expecting more information and more reports by the time of our next meeting, next month in Kuala Lumpur. We are approaching major test events in August and we all need to see progress in this regard.

"I'm not an expert in water pollution, we have to leave it to the experts to tell us what is achievable, and in which time frame. These experts are telling us it is still achievable to have these competitions in safe water conditions and we have been advised today from the local organizing committee that this advice has not changed."

Rio mayor Eduardo Paes said in March that people could be employed to manually clean the bay before the Games if necessary.

According to Paes the Olympic sailing course will avoid areas most affected by sewage and trash.

The 2016 Games, to be held August 5-21, will be the first time the Olympics are staged in South America.