Thick clouds of toxic foam covered parts of a river in southeast Brazil, scattering downwards and worrying residents on Friday. Drone images showed clouds of foam floating on the Tiete River in the town of Salto, the largest river in Sao Paulo with more than a thousand kilometers and crossing the state from east to west. The stinky foamy layer comes from detergent wastes and chemical residues dumped into the river without treatment, according to local media. For all the latest headlines follow our Google News channel online or via the app. The Brazilian NGO SOS Mata Atlantica reported that pollution in a stretch of the Tiete River increased by 40 percent in 2022. In 2021, the polluted area was 85 kilometers. Read more: