CCIL Rupee Yield Curve (Zero Coupon Yield Curve) HELP
  To be able to use the file for portfolio valuation, the software settings in Excel would need to be as under:
a) Macro Security should be set to low (available under Tools/Macro/Security)
b) Analysis Toolpak & Analysis Toolpak – VBA should be selected (available under Tools/Add-Ins)