Which are the categories in which nations are categorized on the basis of HDI?
i. Very High Human Development
ii. High Human Development
iii. Medium Human Development
iv. Low Human Development.

The Human Development Index (HDI) is a composite statistic of life expectancy, education, and income per capita indicators. A country scores higher HDI when the life expectancy at birth is longer, the education period is longer, and the income per capita is higher. It is used to distinguish whether the country is a developed, a developing or an underdeveloped country. The index was developed in 1990 by Pakistani economist Mahbub ul Haq. Countries fall into four broad human development categories: Very High Human Development, High Human Development, Medium Human Development and Low Human Development.