The Riachuelo river, which originates in the Buenos Aires province in Argentina, is one of the most polluted rivers in the world, according to environmental activists.
For decades, tons of industrial and household waste have been dumped into the river, which has become a lifeless sludge.
Among the five million people living alongside the river, an abnormally high number of them have reportedly suffered serious diseases ranging from respiratory problems to cancer.
Last year, the World Bank approved an $840mn loan to the country to help save the river – and now many locals are pushing politicians to implement the job and clean it up for once and for all.
Craig Mauro reports from Buenos Aires.