A canal in a suburb of Argentina’s capital Buenos Aires turned bright red on Thursday, alarming local residents.
Pictures and videos show the intensely coloured water flowing into an estuary, the Rio de la Plata, which borders an ecological reserve.
Local media reports suggest the colour may have been caused by the dumping of textile dye, or by chemical waste from a nearby depot.
The Environment Ministry said in a statement that water samples had been taken from the Sarandí canal to determine the cause of the colour change. (BBC)