Coal could be a flammable black or brownish-black rock, fashioned as rock strata known as coal seams. Coal is generally carbon with variable amounts of alternative parts, primarily gas, sulphur, oxygen, and N. Coal is created once dead plant matter decays into vegetable matter and is born-again into coal by the warmth and pressure of deep burial over various years. Brobdingnagian deposits of coal originate in former wetlands called coal forests that coated a lot of the Earth's tropical land areas throughout the late Carboniferous (Pennsylvanian) and Permian times. However, several important coals deposits square measure younger than this and originate from the Mesozoic and Cenozoic eras. Coal is primarily used as a fuel. Whereas coal has been better-known and used for thousands of years, its usage was restricted till the economic Revolution. With the invention of the externalcombustion engine, coal consumption accumulated. In 2020 coal provided a couple of quarter of the world's primary energy and over a 3rd of its electricity. Some iron and steel creating and alternative industrial processes burn coal.