The UN says the water crisis is so severe that it could take almost 30 years to eradicate hunger from the world.
Although water covers two thirds of the earth surface less than 3 percent is fresh water.
But nearly 70 percent of that is frozen in ice caps and glaciers in polar-regions.
People have access to less than one percent of the world's fresh water.
However pollution is making these limited fresh water bodies unsafe for human use.
While population is rising available clean water supplies are decreasing.
"Water scarcity is becoming a major problem, particularly in the developing countries in the tropical and sub tropical areas due to a host of problems from population growth to changes in climatic conditions," says M. Samad, International Water Management Institute (IWMI).
"This is posing a major threat to world food