Mumbai: Domestic equity benchmarks opened lower on Thursday amid weak global cues and rising geopolitical tensions in West Asia. Sensex opened at 76,515.10, down 239.95 points or 0.31 per cent, while Nifty started the session at 23,904.80, slipping 91.45 points or 0.38 per cent. Oil & Gas, Pharma Among Worst-Hit Sectors Sector-wise, Nifty Oil &.