Natural resource is defined as form of energy and or matter which is essential for the functioning of organisms, population and ecosystems. Natural resource refers to any form of energy or matter essential for the fulfillment of physiological, socioeconomic and culture needs both as undivided or a community.The basic ecological variables - energy, space, 'time and diversity are sometimes combined are called natural resources.This natural resource is maintaining ecological balance among them. The natuial resources include all the land, water, minerals, vegetation, wildlife and sceneries all of which remain useful to human society in one way or other. Natuial resources are classified into following three categories:(1) Renewable resources:Resources that can be replenished through natural cycles are known as renewable resources.These resources are able to increase their abundance through reproduction and utilization of simple substances e.g. Fish, forests, crops, woods, leather, water and soil solar energy, wood and wood products.(2) Non Renewable Resources:Resources that cannot be replenished through natural process are known as non renewable resource.There amount is limited and cannot increased, e.g. Metals (iron, copper, zinc), fossil fuel (coal and oil deposits) minerals and salts (phosphates, nitrates, carbonates) and stone once a non renewable resource is consumed it is gone forever. Non-renewable resources can further be divided into two categories (a) Recyclable and (b) Non-recyclable.