The Indian equity benchmarks gained for sixth straight session on Monday on the back of buying interest in Tata Consultancy Services (TCS), Larsen & Toubro, Tata Motors, Infosys and Mahindra & Mahindra. In the last six sessions, Sensex rose as much as 2,232 points or 3.87 per cent and Nifty 50 index climbed 627 points.