The number of Indian billionaires was more than halved from the previous year.

Forbes counted only 793 billionaires worldwide in 2009, down from last year's 1,125.  World billionaires' net worth, meanwhile, plummeted by about $2 trillion.

Luisa Kroll, senior editor of Forbes, said it was the first time the list had seen such a large drop in billionaires.

"It's really hard to find something to cheer about unless you get some perverse pleasure in realising that some of the most successful ... people in the world ... can't figure out this global economic turmoil better than the rest of us," she said.

Gates 'richest man'

Bill Gates, the founder of software giant Microsoft, regained the title of world's richest man in Wednesday's report, despite losing $18bn in the past year. His fortune now stands at $40bn.

American investor Warren Buffet, meanwhile, slipped to second place after losing $25bn.

Carlos Slim, a Mexican telecommunications tycoon, stands in third place with a fortune of $35bn, down from last year's $60bn.

The only person in the list's top 20 who did not lose money was Michael Bloomberg, the mayor of New York, who saw his fortune rise from $11.5bn to $16bn.

Bloomberg is now reported to be the richest man in New York.