The BSE Sensex rallied over 300 points on sustained buying in realty, telecom, banking, energy and consumer durables counters, ahead of US Federal Reserve's key policy outcome scheduled later in the day.
Bouts of short-covering and firm cues from Asian markets boosted investor sentiment here.
The 30-share index was trading at 33,339.93 at 1100hrs, up 343.17 points, or 1.04 per cent.
The broader Nifty index was trading above the key 10,200 level at 10,222.40, up 98.05 points, or 0.97 per cent.
Major gainers were Bharti Airtel, NTPC, Axis Bank, HDFC and SBI.
Meanwhile, Foreign portfolio investors (FPIs) bought shares worth Rs 344.16 crore on a net basis, while domestic institutional investors (DIIs) also bought equities to the tune of Rs 731.17 crore yesterday, provisional data showed.
Asian shares were trading higher after recent losses amidst caution ahead of Federal decision on policy rates.
US stocks ended higher yesterday, led by strong gains in the energy sector as the overall market reclaimed some lost ground from the previous day.