Houston, Jan 3: Indian business magnate Mukesh Ambani is the 18th richest person in the world with a personal wealth of $24.7 billion in 2012, according to the Bloomberg Billionaires Index, a daily ranking of the world's 100 wealthiest individuals.
Mexican telecommunications magnate Carlos Slim remained the world's richest person last year holding a personal fortune of more than $70 billion, it said.
