The Sensex opened with a positive gap of 23 points at 20,368, which also turned out to be the low for the day. The index hit a high of 20,763 points in late noon deals.The Sensex finally closed with a gain of 342 points (1.7%) at 20,687.The BSE Oil & Gas Index zoomed over 2% ( 315 points) to 13,917.Market breadth was marginally bullish - out of 2,922 scrips traded, 1,483logged gains and 1,416 declined today.INDEX GAINERS....Reliance led the rally today with a gain of nearly 3% (Rs 83) at Rs 2,986.ICICI Bank advanced nearly 5% (Rs 57) to Rs 1,285. L&T gained 4.5% (Rs 183) to Rs 4,244.HUL moved up 3.8% to Rs 231. RCom gained 3.6% to Rs 760. ONGC added nearly 3% at Rs 1,344.Hindalco , ITC and DLF also finished with gains today..... AND LOSERSNTPC declined 1.8% to Rs 272. M&M dropped 1.5% to Rs 823.Infosys was down over 1% at Rs 1,695. TCS and Satyam also declined.MOST ACTIVE COUNTERSReliance Petroleum was the most active counter with a turnover of Rs 431 crore followed by RNRL (Rs 398 crore), Reliance (Rs 272 crore), Centurion Bank of Punjab (Rs 261 crore) and Reliance Energy (Rs 248 crore).