Siberian river has blushed red before, satellite images prove

The river, above the Arctic Circle, was discoloured because heavy rain led to an overflow of a filtration dam at the  Nadezhda Metallurgical Plant, according to Norilsk Nickel which owns the plant.

NASA highlighted images showing a similar colouring of the river in 2001. Landsat satellites also collected images of red discoloration in the waters around Norilsk on multiple dates, including July 2015, July 2014, August 2013, July 1998, and September 1997, said reports.

Norilsk Nickel is taking wide-ranging action to reduce pollution in what has been long seen as a blackspot. The company said short-term river colour staining with iron salts presents no hazards for people and river fauna.