A principal mission of the World Health Organization (WHO) is the promotion of procedures and approaches to planning by governments that can contribute to the improvement of the standard of human health. One of the major developments in recent years has been the use of the environmental impact assessment (EtA) methodology as a means of incorporating environmental considerations into the planning process. This interest was first fanned by the enactment in 1969 of the United States National Environmental Policy Act (NEPA) which contained a provision requiring U.S.A. agencies to carry out environmental impact assessment as part of federal project planning. Subsequently, various expert groups and meetings convened by WHO and other multilateral agencies have concluded that the EIA process can be an effective mechanism to foster human health and welfare considerations in development planning along with economic and technical objectives. The need for analysing possible health hazards and environmental implications in connexion with large-scale socio-economic development projects was further reiterated by the Thirty-fifth World Health Assembly in its Resolution WHA 35.17 (Annex 1).