Fourteen people are on trial in Delhi in one of India's biggest corruption scandals.
The scandal involves the selling of mobile phone frequency licences in 2008, for a fraction of their value.
The group includes a government minister and a member of parliament. All deny any wrongdoing.
Auditors say the matter cost the exchequer nearly $US40 billion in lost revenue.
The BBC reports the scandal has gripped the country and deeply embarrassed the government. A correspondent says everyone is hoping that the trial can be resolved relatively quickly.
The trial is expected to be long and complex. Some 150 witnesses are expected to appear.