Should I go for MDI Gurgaon, if I am already earning 7lpa keeping in mind the fees, and are the placements good enough to cover my opportunity cost for the 2 years?

If you are already earning a salary as high as INR 71 LPA, I don’t think an MBA from MDI Gurgaon will do you any good. If you have decided on going for an MBA nevertheless, target the top B Schools like IIM A, IIM B, IIM C, XLRI, FMS, or IIM L. Choosing MDI for MBA is recommended only if you have offers from average B Schools like new IIMs, SPJIMR, NITIE, etc. 

So first you need to get maximum calls from the top B Schools only then can you make a wise and informed decision.