Define the following terms :
(i) Coliform,
(ii) Sustainable development,
(iii) Chipko Andolan,
(iv) Watershed management.

Explanation

(i) Coliform : A group of bacteria found in human intestines, whose presence in water indicates contamination by disease-causing microorganisms.
(ii) Sustainable development : A pattern of resources used for obtaining economic and social growth of the present generation while preserving the resources for the needs of future generations.
(iii) Chipko Andolan : A grass root level movement in which the villagers used to hug the forest trees and prevent their mass felling by the contractors.
(iv) Watershed management : A scientific method of developing land and water resources to increase the biomass production without causing ecological imbalance.