Housing loan interest treatment

Thank you for reponding but what is the basis of apportion if assessee have 3 room set on ground floor (self occuiped) and 2 room set on first floor (let out)

First split the construction cost based on sq ft.

Then apportion the loan amount based on construction cost for two portions 

Based on above loan amount split the interest

SPILIT ON THE BASIS OF CARPET AREA