1) National income of India constitutes the total amount of income earned by the whole nation and originated both within and outside its territory during a particular year.
2) Estimates of national income are made using various methods including output, income, and expenditure. Data is provided by government agencies and surveys.
3) India's national income has grown significantly since independence, with the economy experiencing periods of modest growth, recovery, and higher growth during the post-reform period from 1992 onward.