Reliance Communications Chairman Anil Ambani was on Tuesday questioned by Parliament's Public Accounts Committee, PAC, in connection with alleged irregularities in the 2G spectrum allocation. Etisalat DB Telecom CEO Atul Jham was also questioned by the panel headed by senior BJP leader Murli Manohar Joshi. The PAC had on Monday quizzed Tata Sons Chairman Ratan Tata and corporate lobbyist Niira Radia in connection with the 2G spectrum scam. S-Tel CEO Shamik Das and Unitech Wireless Managing Director Sigve Brekke are also scheduled to appear before the PAC later in the day.