Today, March 13, the Sensex and Nifty 50 opened lower as investor concerns mounted over rising gas and crude oil prices. The Sensex fell 635 points to 75,341.07, while Nifty slipped 201 points to 23,440.60. Meanwhile, the rupee traded at 91.11 against the US dollar, reflecting cautious market sentiment amid global gas and crude oil price volatility.