Aerial view from a drone showing a pollution stain through the Joatinga channel towards the sea in Barra de Tijuca, Rio de Janeiro, Brazil.
According to experts, the stain is a combination of wastewater, debris, and sediment.
The phenomenon is recurrent at low tides, which occur on full and new moons, and can last up to five days.
Via EPA-EFE/Antonio Lacerda
