What is air pollution and what are the causes and effects of for air pollution?

An increase in the content of harmful substances in air is called air pollution.
The various reasons for air pollution and their effects are given below: • The fossil fuels like coal and petroleum contain small amounts of nitrogen and sulphur. When these fuels are burnt, nitrogen and sulphur too are burnt and this produces different oxides of nitrogen and sulphur. These gases also dissolve in rain to give rise to acid rain.
• The combustion of fossil fuels also increases the amount of suspended particles in air. These suspended particles could be unburnt carbon particles or substances called hydrocarbons.
• Presence of high levels of all these pollutants causes visibility to be lowered, especially in cold weather when water also condenses out of air. This is known as smog and is a visible indication of air pollution. • A regular breathing of air that contains any of these substances increases the incidence of allergies, cancer and heart diseases.