Land, water, air, plants, animals, solid wastes and other things that are surrounding us constitute our environment. When physical scientists talk about environment they generally refer to the physical environment that comprises the three inter locking systems the Atmosphere, the Hydrosphere and the Lithosphere. Biologists often refer to biological environment consisting of all living organisms of the Biosphere. Similarly social scientists refer to the social, cultural, economic and organizational environment. Hence environment may be defined as the sum of all social, cultural, economical, biological, physical and chemical factors surrounding the 'man' to give necessary protection to him. Two types of environment we may come across. One is the natural environment of the air, water, solid wastes, noise, radiation, soil, timber, wildlife and living space etc. Man and environment are closely intertwined with each other, to maintain a balance or equilibrium in nature. Different groups of people working in different areas express it in various ways. Advertisements: Environment means the surroundings.