The sustainment of all things living is due to a combination of gases that collectively form the atmosphere; the imbalance caused by the increase or decrease of the percentage of these gases can be harmful for survival. Pollution is an issue of concern in the modern world that we live in today. There are many types of pollution, namely air, water and noise. Pollution in our environment will undoubtedly affect our quality of life. Our naturally beautiful world becoming ugly because it is suffering from the effects of environmental pollution. Pollution can also cause various health problems and other negative effects. Environmental pollution is a multi-disciplinary science involving chemistry, physics, life science, agriculture, medical science, public health, sanitary engineering etc. In broader sense, it is the study of the sources, reactions, transport, effect and fate of chemical species in the air, water and soil and the effect of human activity upon these. Pollutant A substance present in nature, in greater than natural abundance due to human activity, which ultimately has a detrimental effect on the environment and therefrom on living organisms and mankind. Examples are- lead, mercury, sulphur dioxide, carbon monoxide, etc. Contaminant A material which does not occur in nature, but is introduced by human activity into the environment, affecting its composition. A contaminant is classified as a pollutant when it exerts a detrimental effect. Example- chlorine gas Causes of Air Pollution 1. Burning of Fossil Fuels: Sulfur dioxide emitted from the combustion of fossil fuels like coal, petroleum and other factory combustibles is one the major cause of air pollution. Pollution emitting from vehicles including trucks, jeeps, cars, trains, airplanes cause immense amount of pollution. We rely on them to fulfill our daily basic needs of transportation. But, there overuse is killing our environment as dangerous gases are polluting the environment. Carbon Monoxide caused by improper or incomplete combustion and generally emitted from vehicles is another major pollutant along with Nitrogen Oxides, that is produced from both natural and man made processes. 2. Agricultural activities: Ammonia is a very common by product from agriculture related activities and is one of the most hazardous gases in the atmosphere. Use of insecticides, pesticides and fertilizers in agricultural activities has grown quite a lot. They emit harmful chemicals into the air and can also cause water pollution. 3. Exhaust from factories and industries: Manufacturing industries release large amount of carbon monoxide, hydrocarbons, organic compounds, an