The atmosphere is a complex, dynamic and fragile system. Before learning air pollution, it is essential to understand the composition of atmospheric gases. The following picture illustrates the same.
Air is a mixture of gases predominantly constituting Nitrogen and Oxygen. Any drastic change in this composition in a area, that may result in harm or discomfort to the inhabitants is said to be air pollution.
Though air pollution can happen both naturally and due to human activities, we are bothered about the latter, because we can control it.