Reliance Industries Chairman and Managing Director Mukesh Ambani has regained the top spot in Asia's richest person list, dislodging fellow Indian industrialist Gautam Adani from the eighth spot in the world's richest. Mr Ambani has a net worth of $99.7 billion according to the Bloomberg Billionaire Index. With a $98.7-billion net worth, Mr Adani has slipped to the ninth spot.