The world depends on a limited quantity of fresh water. Although water covers 70% of the earth’s surface, only 3% of this is fresh water. Of this, 2% is in polar ice caps and only 1% is usable water in rivers, lakes and subsoil aquifers. Only a fraction of this can be actually used.

Reasons for environmental resource water depletion:

• Increasing population:

World population has crossed 7 billion and is increasing. This places enormous demands on the world’s limited freshwater supply.

• Overutilization of water:

Overutilization of water occurs at various levels. Most people use more water than they really need. Most of us waste water during a bath by using a shower or during washing of clothes. Many agriculturists use more water than necessary to grow crops.

• Pollution of surface and groundwater:

Agriculture also pollutes surface water and underground water stores by the excessive use of chemical fertilizers and pesticides. Industry tends to maximise short-term economic gains by not bothering about its liquid waste and releasing it into streams, rivers and the sea.

• Global climate change:

Changes in climate at a global level caused by increasing air pollution have now begun to affect our climate. Everywhere the ‘greenhouse effect’ due to atmospheric pollution is leading to increasingly erratic and unpredictable climatic effects. This has seriously affected regional hydrological conditions.