Coal is the most abundantly available fossil fuel in India. Importance of its different forms are as follows
• Decaying plants in swamps produce peat.
• It is burnt as fuel or applied to the soil to improve the texture or raise its water-retaining property.
• It has 60-70% carbon, brown in colour, soft and having high moisture content.
• It is used for electricity generation.
• It has lowest heat content per kg.
• It is used for commercial purpose especially ideal for smelting iron in blast furnaces.
• It has 75-90% carbon content, dense sedimentary rock, usually black in colour and has medium heat content per kg.
• It is also used as making coke.
• It is used in the metal smelting and fabrication industries especially used as a reduction agent for various applications i.e. briquetting charcoal, iron-ore pellets and other uses.
• It has more than 90% carbon content per kg and its heating content per kg is highest.
• It is also used in residential and commercial space heating.