The waterway in the suburbs of Buenos Aires, the capital of Argentina, turned into a bright red on Thursday, surprising locals.
Sarandí Canal flows through residential and industrial areas and reached RIO de la Plata, a high ear, to reject ecological reserve.
Local media reports may be caused by dumping of fiber dyes or chemical waste in nearby warehouses.
The authorities collected samples to determine pollution sources.
Read more: Argentina canal turns bright red
