• Natural Resources: Resources include everything provide by the nature. They form the wealth of a country.
• Types of Natural Resources:
(i) Inexhaustible: There are some resources that are present unlimited in nature and will not be exhausted even if used continuously. Example: Sunlight, Air.
(ii) Exhaustible: These resources are limited and can soon get exhausted because of their excessive use. Example: Forests, wildlife, minerals, coal, petroleum, etc.

• Coal, petroleum and natural gas are fossil fuels.
• Fossil fuels were formed from the dead remains of living organisms millions of years ago.
• Fossil fuels are exhaustible resources.
• Coke, coal tar and coal gas are the products of coal.
• Petroleum gas, petrol, diesel, kerosene, paraffin wax, lubricating oil are obtained by refining petroleum.
• Coal and petroleum resources are limited. We should use them judiciously.
• Refining: Petroleum is mixture of various constituents such as petroleum gas, petrol, diesel, lubricating oil, paraffin wax, etc. Refining is the process of refracting the various constituents / fractions of petroleum. It carried out in a petroleum refinery.
• Natural Gas: A very important fuel as it easy to transport through pipes and can be compressed and stored under high pressure as Compressed Natural Gas. It causes no pollution and has high calorific value.