Environment impact assessment (EIA) is a tool used for decision making regarding developmental projects and programmes and it may be defined as formal process used to predict the environment consequences of any development project.

ELA is intended to identify the environmental, social and economic impacts of a proposed development prior to decision making.

Need of EIA - to maintain the quality of environment it is essential that the prospective impacts of the project on natural environment are studied on time and remedial measures be taken so as to promote sustainable development of the projects. This is done through EIA.

For example, a forest ecosystem is a complete ecosystem which provides food, shelter to a wide variety of species. It provides firewood, resins etc. to us. Therefore forests are our lifelines. Whenever a project undertaken which demands clearing of the forest like construction of road or dam, then EIA helps us to assess the impact of that activity on this life line. It also suggests alternate project sites and alternative process technologies.