What do you actually mean by CONSERVATION ??

Conservation: Sustainable use of natural resources.

what is sustainability?
Capable of being continued with minimal long-term effect on the environment.

Natural Resources:Natural resources are of two main types, renewable and non-renewable.

Renewable resources are inexhaustible or replaceable by new growth. These include wildlife and natural vegetation of all kinds. The soil itself can be considered a renewable resource, although severe damage is difficult to repair because of the slow rate of soil-forming processes. The natural drainage of waters from the watershed of a region can be maintained indefinitely by careful management of vegetation and soils, and the quality of water can be controlled through pollution control.

Non-renewable resources are those that cannot be replaced or that can be replaced only over extremely long periods of time. Such resources include the fossil fuels (coal, petroleum, and natural gas) and the metallic and other ores.