Why is coal often used near the source of its mining whereas mineral oil is transported to great distances?

Name the region in which India's main coalfields are located. What is the quality of coal found here? What are its uses?

What is meant by hydel power?

With reference to the Bhakra Nangal Dam, answer the following:

(i) Name the river on which it has been constructed.

(ii) Name two states that benefit from this project.