Treatment of arrears and unrealised rent: treated as income from house property when received, with a prescribed deduction. Arrears of rent and unrealised rent realised subsequently shall be deemed income from house property in the financial year in which received or realised and included in total income under the head 'Income from house property' whether or not the assessee is the owner; a sum equal to thirty per cent of such arrears or unrealised rent shall be allowed as a deduction.