In demonstrations timed to coincide with World Environment Day, activists are demanding the State Government fulfil their pledges to clean the Bay, a key aspect of Rio's initial bid for the Games in 2009.

To the sound of whistles and horns, dozens of protesters marched with a banner, reading: "One billion dollars and it's still disgusting".

With better planning and organisation, progress can be made while maintaining current levels of investment, they claim.

Pollution on the Bay is a two-fold problem, consisting of sewage entering the Bay through various rivers, lakes and lagoons, as well as physical rubbish also being deposited.

While the former problem requires a more fundamental overhaul, the latter issue would seem to be more easily solved.

But, despite hiring an external Dutch company to identify areas on the Bay where the build-up of rubbish is highest, State Government officials responsible for reducing levels have failed to sign a contract to purchase boats to collect this rubbish, throwing plans into jeopardy.

This is despite a vow to reduce pollution levels by 80 per cent having been a key part of the Rio 2016 Olympic legacy, with Rio Mayor Eduardo Paes having described this as a "missed opportunity".

The failure also presents problems for the sailing competition, due to take place on the Marina da Gloria site on the Bay.

Rio 2016 Organisers have now taken over responsibility for reducing pollution from the Government, but are only working on the specific competition area ahead of a scheduled test event in August. 

International Sailing Federation (ISAF) officials have expressed their concerns about Guanabara Bay and President Carlo Croce and vice-president Scott Perry met with International Olympic Committee (IOC) officials, including President Thomas Bach, to discuss the issue.

Severe concerns have been expressed by athletes and officials, with some even calling for the event to be moved elsewhere further out to sea. 

Others have said that, however, that despite the problems, sailors are prepared and used to competing in all conditions, with the wider failure to reduce levels therefore a greater worry.

The issue is nonetheless considered a foremost remaining challenge with little more than a year to go until the first South American Games and it is set to be discussed here today at the IOC Executive Board meeting.

IOC vice-president and Rio 2016 Coordination Commission chair Nawal El Moutawakel is due to provide a progress report.

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