In India, tertiary coals occur in Assam, Arunachal Pradesh, Nagaland and ______.

The correct answer is Meghalaya . Key Points In India, tertiary coals occur in Assam, Arunachal Pradesh, Nagaland, and Meghalaya. Tertiary coal is found in the rocks of the Oligocene period of the Tertiary Era. Tertiary coal fields share only 1% of the coal production of India. Tertiary coal is also known as 'brown coal'. Tertiary coal contributes only about two per cent of the total coal production of the country. Hence, option 2 is correct. Additional Information Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is the foremost power resources in India and is the most abundantly available fossil fuel. India is highly dependent on coal for meeting its commercial energy requirements. Coal is found in a variety of forms depending on the degrees of compression and the depth and time of burial. Types of Coal : Anthracite (more than 80% carbon content): In India, it is found only in Jammu and Kashmir. Bituminous (60 to 80 % Carbon Content): It is the second-best quality of coal. It is the most popular coal in commercial use. Peat (less than 40% carbon content) Lignite : It is low-grade brown coal, which is soft with high moisture content. The principal lignite reserves are in Neyveli in Tamil Nadu and are used for the generation of electricity. The Damodar Valley Coalfield is the largest coalfield in India that extended to Jharkhand and West Bengal. Jharia in Jharkhand is the largest coal mining field .