Pollution

Definition

Presence of matter (gas, liquid, solid) or energy (heat, noise, radiation) whose nature, location, or quantity directly or indirectly alters characteristics or processes of any part of the environment, and causes (or has the potential to cause) damage to the condition, health, safety, or welfare of animals, humans, plants, or property.

Pollution is the introduction of contaminants into an environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms. Pollution can take the form of chemical substances, or energy, such as noise, heat, or light energy. Pollutants, the elements of pollution, can be foreign substances or energies, or naturally occurring; when naturally occurring, they are considered contaminants when they exceed natural levels. Pollution is often classed as point source or nonpoint source pollution.

Introduction
There are two types of the cause of pollution, natural and man-made. Natural pollution occurs naturally and won't cause excessive harm to our lives due to its regeneration ability. While the man-made pollution is caused by human activities, and hard to get rid of. The backbones of man-made pollution are human population and technology. Naturally human needs contact to the environment, we get resources from nature. This is for the sake of living. By the increase of human population, the contact is getting more intensive, because needs are increasing. And by the findings and development of new technologies, human can apply them to get the resources. And it's common that new technologies would bring their respective side effects besides their advantages. 
Small population with any level of technology wouldn't have to exploit the nature overwhelmingly. But big population with any level of technology will surely exploit the nature more, and even overwhelmingly, this is all for the needs of the people.
Pollution is a growing pain. Pollution is not a problem that came suddenly from the sky; it's our fault and has been a part of our life through many years. We must be wise in managing our resources, and take positive action towards preventing any forms of pollution to the environment. Make the world a better place to live.

There are 6 (six) types of pollution that are going to be discussed in this site, namely air, water, noise, land, radioactive, and thermal.