Rio de Janeiro's mayor has admitted that the much-touted goal of cleaning up the Brazilian city's blighted waterways in time for the 2016 Olympics will probably not be met, with just 500 days until the games begin.
Eduardo Paes told SporTV that cleaning up Guanabara Bay, the sewage and rubbish-infested channel where the Olympic sailing events are to be held, "is something that we should have been able to achieve".
"It is indeed a wasted opportunity," he said, adding: "As a Rio resident, I think it's a shame."
Without a well-developed sewage collection and treatment system or reliable rubbish collection in the sprawling urban area that rings the bay, tons of mess and raw sewage flow into the bay, as well as other area waterways - including Rio's world famous beaches.
While the first government programmes to clean up the bay date back more than 20 years, little progress was made. But in Rio's Olympic bid, authorities promised a massive clean-up effort that would be an enduring legacy of the games.
But as the games have drawn nearer with little evidence of progress and an often-changing plan for slashing the flow of raw sewage, officials from the governor to the state's environmental chief have voiced their scepticism that the Olympic promises could still be met.
Now Mr Paes added his voice to the chorus on the eve of the 500th day before the games kick off in Rio.
Athletes too, have sounded the alarm bells about water conditions in Guanabara Bay, with many worried about falling ill from the spray of the sewage-filled water, as well as potential collisions with floating rubbish.
But Olympic officials have continued to insist that the promises would be met and the brackish waters of the bay cleaned up for the games.
Still, Mr Paes was careful to say the waters would not pose a risk to Olympic athletes, emphasising that the events would be held in the cleanest part of the bay.
But a helicopter ride organised by biologist and environmental activist Mario Moscatelli illustrated the extent of the problem, revealing household waste floating throughout the entire bay, including within lanes for the Olympic sailing competition.
Heavy rains in Rio over the weekend exacerbated the problem. Each time the tropical city sees heavy rains, the amount of raw sewage emanating from the city's 1,000-plus "favela" slums spikes and huge amounts of rubbish are flushed off the streets and into area waterways.
Canals were overflowing with sewage yesterday, their murky waters staining the sapphire blue waters of the Atlantic ocean off the the golden sands of a popular beach in the Barra de Tijuca neighbourhood, one of the main Olympic hubs.
In Guanabara Bay, an oil slick trailed a boat for miles. The vessel was caught on camera by an Associated Press photographer and reported by Mr Moscatelli to Rio's environmental agency, which said it would levy the biggest possible fines against the vessel's owners.