What are the disadvantages of thermal power plants?

Q. Statement 1: Vindhyachal thermal power station is set up near the northern coalfields in Madhya Pradesh.

Statement 2: Thermal power plants are dependent on coal and the proximity of coalfields to the plants helps cut transportation costs.

Q. Despite having large reserves of coal, why does India import millions of tonnes of coal?
1. It is the policy of India to save its own coal reserves for future, and import it from other countries for the present use.
2. Most of the power plants in India are coal-based and they are not able to get sufficient supplies of coal from within the country.
3. Steel companies need large quantity of cooking coal which has to be imported.

Which of the statements given above is / are correct?