Disposal of Armenian bodies on rivers was viewed by the authorities as a cheap and efficient method, but it gave rise to widespread pollution downstream. So many bodies floated down the Tigris and Euphrates rivers that they sometimes blocked the rivers and needed to be cleared with explosives. Other rotting corpses became stuck to the banks of the rivers while some traveled as far as the Persian Gulf. Long after the massacres, the rivers remained polluted and Arab populations downstream were affected by epidemics.