Mass amounts of dead fish have washed up on the shores of the Rodrigo de Freitas lagoon in Rio de Janeiro, intended to be the site for rowing and canoe competitions during the 2016 Olympics, according to CNN.
Rio’s legislative assembly have begun investigating the cause, alongside the State Environmental Institute and the Secretariat of State for the Environment.
Officials believe that recent rainfall changed the temperature of the water and increased the amount of “decaying organic matter,” reducing the oxygen available and killing the fish.
The deaths have led to a “bad smell and inconvenience” for residents of the area and tourists alike.
This isn’t the first troubling problem Rio has faced. Last week, two professional sailors crashed into garbage floating in the waters of Guanabara Bay. A video showed the boat tipping onto its side from the impact.
Last year, biologists also brought attention to a superbacteria in the rivers that feed into Guanabara. It’s resistant to antibiotics and can lead to urinary, gastrointestinal, and pulmonary infections.
Mayor Eduardo Paes told SporTV, Brazil’s largest sports channel, that he doesn’t see the pollution in the area causing a problem for the Olympics next year.