Former telecoms minister Andimuthu Raja of India and three major mobile phone companies have been charged with conspiracy, forgery and fraud in connection with a corruption scandal.
The charges relate to the sale in 2008 of mobile phone licences for a fraction of their real value.
Auditors believe the Indian government may have lost almost $US40 billion in lost revenue.
Mr Raja has denied the charges. Last year he was forced to resign over the issue.
Investigators say Mr Raja deliberately favoured some companies over others when allocating valuable second generation (2G) mobile phone licences.
He is accused of issuing 2G licences on a "first-come, first-served" basis instead of auctioning them.
The BBC reports India has the world's fastest growing mobile market, with about half a billion subscribers.
