Indexed Cost of Property

As i could observed in few ready reckoners from VinodKSinghania & Nabhi Publications, that interest on borrowed capital is also the part of cost of the asset and hence would also be indexed for calculating the indexed cost.

I just want to know, how the calculations need to be done for the same, i.e.

1/ Does the EMI need to be indexed, Year-over-year's CII

2/ Does the Principal be indexed in the first year's CII, and interest be indexed Y-o-Y's CII

3/ Does both the principal & interest be indexed by first year's CII

Thanks

Ankit