Thar Desert natural vegetation of this dry area is classed as Northwestern thorn scrub forest occurring in small clumps scattered more or less openly. Density and size of patches increase from west to east following the increase in rainfall. The natural vegetation of the Thar Desert is composed of the following tree, shrub and herb species: The endemic floral species include "Calligonum polygonoides", "Prosopis cineraria", "Acacia nilotica", "Tamarix aphylla", "Cenchrus biflorus". The Thar Desert is the most widely populated desert in the world, with a population density of 83 people per km. In India, the inhabitants comprise Hindus, Muslims, and Sikhs. In
Thar coalfield metres and rests upon a structural platform in the eastern part of the desert. The generalised stratigraphic sequence in the Thar coalfield area is shown in table. It comprises Basement Complex, coal bearing Bara Formation, alluvial deposits and dune sand. The coal beds of variable thickness ranging from 0.20–22.81 metres are developed. The maximum number of coal seams found in some of the drill holes is 20. The cumulative thickness of the coal beds range from 0.2 to 36 metres. Claystone invariably forms the roof and the floor rock of the coal beds. The coal is brownish black, black and