Indian equity benchmark indices, the Sensex and Nifty, started the session in green even as global cues remain challenging. The 30-share BSE Sensex gained 120.03 points, or 0.16 per cent, to open at 74,849.30, while the Nifty added 4.70 points to open at 23,150.85. In the last trading session, the Sensex closed at 74,729.27 and the Nifty 50 at 23,146.15.