The BSE benchmark Sensex nosedived about 1,940 points to settle just above the 49,000-level on Friday, tracking massive sell-offs in world equities after a rout in global bond markets spooked investors. Similarly, the broader NSE Nifty plunged 568.20 points or 3.76 per cent to close the session at 14,529.15. ONGC was the top loser, shedding around 6.50 per cent, followed …