Looking Down On Polluted Waters

The UN estimates that around 4 billion people experience severe water shortages for at least one month a year and around 1.6 billion people - almost a quarter of the world's population - have problems accessing a clean, safe water supply.

The UN's Sustainable Development Goals call for water and sanitation for all by 2030, but they say water scarcity is increasing and more than half the world's population will be living in "water-stressed" regions by 2050.

Reuters photographers used drones to capture dramatic pictures and video of polluted waterways around the world.