Indian stock markets opened sharply lower amid tensions between US and Iran and concerns over crude oil supply through Strait of Hormuz. The Sensex plunged 62 points to 76,427, while Nifty 50 slipped 16 points to 24,015. Bank Nifty gained 78 points to 55,372. The rupee weakened by 15 paise to 95.25, reflecting a broad risk-off mood across global markets today.