Taxable income.

Hello,

I am thinking of buying a commercial property within next 2 months (before march 31) and my question is that if my total income at the end of the year is 20 lacs and I buy a commercial property for 10 lacs and I am left with 10 lacs. Would I be paying tax on the whole 10 lacs since commercial property is a fixed asset or do I have to pay tax on the whole 20 lacs.