From financial year 2016-17 section 25B is merged into section 25A.
Provisions till financial year 2015-16
When the assessee cannot realise rent from a house property and the assessee has realised any amount in respect of such rent in any subsequent years, then such income shall be deemed to be the income from house property, in the year of receipt.
No standard deduction u/s 24a shall be allowed. Therefore 100% of such sum received will be taxable.
The income shall be taxable Irrespective of whether or not the assessee is the owner of the property in that year.