Now, the 62-year-old Indian billionaire and a close ally of Prime Minister Narendra Modi, whose sprawling $169bn empire spans ports and renewable energy, faces US fraud charges that could potentially jeopardise his ambitions at home and abroad.

India's Adani Group on Thursday called US charges that their billionaire tycoon founder Gautam Adani had paid more than $250 million in bribes "baseless", as the opposition leader demanded his arrest.

Gautam Adani, the billionaire chair of Indian conglomerate Adani Group and one of the world's richest people, could face a long road to trial in the U.S. on criminal charges over his alleged role in a multi-billion-dollar fraud and bribery scheme.