Besides, a firming trend at other Asian markets following weekend sharp gains in US on the back of upbeat earnings, buoyed the sentiments here.
The 30-share Sensex zoomed by 392.51 points, or 1.50 per cent, to trade at 26,501.04. The gauge had gained 109.19 points in Friday's trade.
All the sectoral indices, led by PSU and oil & gas, were trading in the positive territory with gains up to 2.83 per cent.
Brokers said sentiments turned bullish on the back of oil and gas reforms announced by the government and BJP's stellar show in the Assembly elections in Haryana and Maharashtra.
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In the oils and gas segment, stocks of ONGC climbed 5.26 per cent, GAIL (2.04 per cent) and Oil India Ltd (2.27 per cent).
Meanwhile, in a major reform push, the government on Saturday deregulated diesel prices but hiked natural gas tariff by 46 per cent that will push up fertiliser, power, CNG and PNG rates.
The US Dow Jones Industrial Average gained 1.63 per cent in Friday's trade.