Which is the highest quality hard coal, with the highest carbon content?

Coal is a fossil fuel formed over millions of years from the remains of ancient plants that were buried under layers of sediment and subjected to heat and pressure, mainly during the Carboniferous period (about 300 million years ago) and, in India, the Gondwana period. This process is called coalification. As coal is buried deeper and longer, it loses moisture and volatile matter and its carbon content increases.

Coal is classified into four main types, based on carbon content and quality:

Peat: the first stage of coal formation, formed from partly decayed plant matter in wet, marshy areas. It has low carbon content (below 40-55%), high moisture, and burns with a lot of smoke and little heat.

Lignite (brown coal): low-grade coal with about 40-55% carbon and high moisture. It is soft and brown. In India, Neyveli in Tamil Nadu has the largest lignite deposits, used to generate electricity.

Bituminous coal: the most widely used commercial coal, with about 60-80% carbon. It is black and dense. Coking coal, a type of bituminous coal, is used in the iron and steel industry. Most of India's coal is bituminous, found in the Gondwana coalfields.

Anthracite: the highest grade of coal, with about 80-95% carbon. It is hard, black and shiny, has very little moisture and volatile matter, burns with a short blue flame, gives the most heat and produces little smoke. In India, it is found only in small amounts, mainly in Jammu and Kashmir.

India has the fifth-largest coal reserves in the world and is the second-largest producer and consumer of coal, after China. Coal production crossed 1 billion tonnes in 2023-24. Most of India's coal comes from the Gondwana coalfields of the Damodar valley (Jharia, Raniganj and Bokaro), and from the Mahanadi, Son and Godavari valleys. Jharkhand has the largest coal reserves, followed by Odisha and Chhattisgarh. Coal India Limited, set up in 1975, is the largest coal producer in the world.

Why not the other options?

• ✗Bituminous coal is the most commonly used commercial coal.
• ✗Lignite is a low-grade brown coal.
• ✗Peat is the lowest grade, the first stage of coal formation.