The Central Bureau of Investigation (CBI) team in New Delhi has started quizzing the Corporate lobbyist Niira Radia in connection with the 2G spectrum scam. Our correspondent quoting official sources reports, a team of CBI officials are now questioning her on several issues including her alleged involvement in the spectrum allocation. She along with former telecom minister A Raja was served CBI summons yesterday to appear before it for questioning. The CBI also yesterday grilled former TRAI chief Pradip Baijal . Earlier, the Enforcement Directorate too had grilled Radia about her role in the spectrum allocation. The CBI earlier raided over 30 places in Delhi and Tamil Nadu on December 15 and questioned several persons informally. In the just concluded winter session of the Parliament, the CAG report on 2G spectrum scam was tabled. The report has pegged a huge revenue loss to the exchequer .