Indian tycoon and one of Asia's richest men, Gautam Adani, may be facing his biggest challenge yet with an indictment by U.S. prosecutors for alleged fraud and bribery. But it was unclear just how far the implications will affect his businesses and own future — as well as the Indian economy and government.

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.

A US indictment threatens Indian tycoon Gautam Adani’s efforts to redefine himself as a clean-power champion and secure overseas financing for projects vital to the nation’s energy transition.