The billionaire founder of one of India’s biggest business conglomerates has been charged in a newly unsealed indictment with running a years-long $250 million bribery scheme to secure solar energy contracts projected to bring him billions in profits.

Prosecutors allege that Gautam Adani—a close ally of Indian Prime Minister Narendra Modi and chairman of the Adani Group—personally met with Indian officials and promised them millions in bribes. Modi is not charged with any wrongdoing.