Now-a-days, you might have heard every one talking about pollution. What does pollution mean? Pollution is the addition to the environment (air, water, soil) of substances or energy (heat, sound, radioactivity, etc.) at a rate, and in quantities that are harmful to life.
Pollution has a long history. It became noticeable when larger and largcr numbers of peoplbegan to live in cities. Unplanned growth of the cities,led to difficulties in the disposal of garbage and sanitary wastes. Living space was often shared with animals as is sometimes done in lndia even now. Mud, slush and dusty roads added to the pollution. Air, water and soil, acquired many harmful substances, in the form of wastes, from human activities. The waste materials (pollutants) that cause pollution are of two types:
i) those that remain in an unchanged form for a long time and are known as persistent pollutants, e.g. pesticides, nuclear wastes, and plastlcs etc. Many of these are toxic;
ii) those that break down, into simple products, and are known as non-persistent pollutants, e.g., garbage. If this break down process is facilitated by living organismsthen such pollutants are referred to as biodegradable pollutants, e.g., wastes from animal sheds.
Pollution has disturbed the ecological balance in so inany ways that can be disastrous for mankind. Presently, we have reached a stage where we must begin to protect our environment in order to protect ourselves. In the following pages, you will study how different wastes have entered into air, water and soil, and how noise and radiation have caused immense damage to our environment, and ultimately to us.