World Water Day is being celebrated Wednesday to coincide with the end of the Fourth World Water Forum which opened in Mexico City last week. The United Nations warned Tuesday that water shortages are leading to more problems than simply a lack of fresh drinking water.

The UN Environmental Programme’s Global International Waters Assessment (GIWA) report released Tuesday said: “Freshwater shortages are likely to trigger increased environmental damage over the next 15 years.”

The list of dangers ranges from severe pollution, species loss and even food security, with billions of people around the world already faced with severe freshwater shortages, triggered by massive damming and depleted aquifers, reports AFP.

UN figures reveal that some 1.1 billion people already go without safe drinking water and 2.6 billion, or 40 per cent of the world’s population, lack decent sanitation.

Further environmental problems including falls in river flows, rising saltiness in biologically-rich estuaries, and the reduction in coastline sediment.