Conservation group WWF said that unexplained toxic pollution off Russia's far eastern coast was likely caused by a highly soluble substance.
Officials played down the scale of the problem and suggested it was not manmade.
Joe Davies reports.
Conservation group WWF said that unexplained toxic pollution off Russia's far eastern coast was likely caused by a highly soluble substance.
Officials played down the scale of the problem and suggested it was not manmade.
Joe Davies reports.