Why are petro-chemicals so important?

Many useful substances are obtained from petroleum and natural gas. These are termed as ‘Petrochemicals’. These are used in the manufacture of detergents, fibers such as polyester, nylon, acrylic etc., polythene and other man-made plastics. Hydrogen gas obtained from natural gas is used in the production of fertilizers such as urea. Due to its great commercial importance, petroleum is also called ‘black gold’.