Answer: In economics, a variety of methodologies of national income as well as output are used to measure complete economic operation in a region or country, including GDP, GNP, (NNI) net national income, as well as altered national income (NNI modified for the depletion of natural resources – also known as NNI at factor cost). All are particularly interested in calculating the total quantity of goods as well as services generated within the economic system and by different sectors.In India, the national income estimate is conducted by the Central Statistical Organization (CSO).