While water is a renewable resource, it is at the same time a finite resource. The total quantity of water available on the globe is the same as it was two thousand years ago.
It is important to appreciate the fact that only 3 per cent of the world’s water is fresh and roughly one-third of it is inaccessible. The rest is very unevenly distributed and the available supplies are increasingly contaminated with wastes and pollution from industry, agriculture and households.
Over the years, increasing population, growing industrialisation, expanding agriculture and rising standards of living have pushed up the demand for water. Efforts have been made to collect water by building dams and reservoirs and creating ground water structures such as wells. Recycling and desalination of water are other options but cost involved is very high.