Pre-construction interest on housing loan

only Rs 2 lakhs.  this limit is inclusive of pre-construction interest.

If you are receiving possession in Previous Year 2014-15,

Int paid during P. Y. 14-15 wont be considered as pre construction int. 

And you have to claim benefit u/s 24 for PY 14-15 itself

Explanation.—Where the property has been acquired or constructed with borrowed capital, the interest, if any, payable on such capital borrowed for the period prior to the previous year in which the property has been acquired or constructed, as reduced by any part thereof allowed as deduction under any other provision of this Act, shall be deducted under this clause in equal instalments for the said previous year and for each of the four immediately succeeding previous years:

I am not expert, wait for others view

I agree with Roopali.  Since you got the possession of the house in March 2015, it means that there is no pre construction period in your case.  You can claim Rs.2 lakhs in FY 2014-15 and another Rs.2 lakh in 2015-16.  

Roopali and Akhil are right. There is no pre construction interest in your case