Concern for environmental pollution is rather a recent phenomenon which has been triggered mainly by the
backlash effect of accelerated industrial growth in the developed countries. The two major criteria-the project
should maximise economic returns; and it should be technically feasible-are no longer considered adequate to
decide the desirability or even the viability of the project. It is now widely recognised that the development effort
may frequently produce not only sought for benefits, but either-often unanticipated-undesirable consequences as
well which may nullify the socio-economic benefits for which the project is designed.