Mr Mittal was born to a poor family in Rajasthan in 1950

It put Mr Mittal's fortune at $51bn (�25bn), double last year's level.

The net worth of India's 40 richest people now totals $351bn, with the top three alone worth more than China's top 40, who have a net worth of $120bn.

India now has 54 billionaires, 18 more than last year, and they were helped by stock market gains and a strong rupee.

The stock market has roared 53% higher in the past year, and a rupee has appreciated 12% during the same period, Forbes Asia said.

Table positions

Mukesh Ambani of Reliance Industries is snapping at Mr Mittal's heels in second place.

His net worth grew at a faster pace than Mr Mittal's last year to a total of $49bn.

Mr Ambani's estranged brother, Anil, ranks third, with his net worth rising by $30.2bn to $45bn.

Kushal Pal Singh is fourth on list with a net worth of $35bn, making him the world's richest real-estate developer.

Mr Singh's wealth has more than tripled from the $10bn he had last year after his company, DLF, listed on the stock market in June this year and its stock surged 60% in value.

Dropping one place to fifth position is Azim Premji, the head of technology giant Wipro who is currently valued at $14.8bn, up from $14bn last year.