Normally a nation is considered rich, when its GDP (Gross Domestic Product) per capita (per person per annum) is higher. The most commonly accepted method of determining the wealth of countries and comparing generalized differences in living standards on a whole between nations is to use GDP per capita on a purchasing power parity basis in current international dollars.
The Gross Domestic Product(GDP) measures the total value, calculated in dollars, of all final production in a country. It can be calculated in three ways: by adding up income and profits received from production of goods and services.
By that measure it is estimated that in 2013 the richest nation in the world was Qatar, with a per capita GDP (PPP) of over 105 thousand dollars, while the poorest was the Democratic Republic of Congo, with less than 400 dollars. India stands in 126th position in the World Bank list with a per capital GDP of $ 3876.