Explanation:

Most of the Indian coals contain higher percentage of inorganic impurities compared to the coals of western world and Australia. Indian coals have a high ash content and a high ash fusion temperature which varies from 35 to 45 per cent, compared with that of coal in other parts of the world, which is around 15 per cent.

 However, Indian coal’s sulphur content is low, Sulphur content of Indian coal is, in general, around 0.5 – 1%. Poor wash ability characteristics, generally low alkali content, and from a slag viscosity perspective, a favorable silica-alumina ratio.