TCS is kick-starting the December quarter results calendar on Thursday. Falling for the second straight day, the 30-share benchmark dropped 528.28 points or 0.68 per cent to sink below the 78,000 level at 77,620.21. During the day, it tanked 605.57 points or 0.77 per cent to 77,542.92. The NSE Nifty slumped 162.45 points or 0.69 per cent to 23,526.50.