House property deductions govern standard allowance, borrowed-capital interest, and compliance-linked limits on interest deduction. Income from house property is computed after a standard deduction of 30% of the annual value and deduction of interest on borrowed capital used to acquire, construct, repair, renew or reconstruct the property. Prior-period interest is allowed in five equal instalments, subject to special caps for properties under section 21(6), certificate requirements, adjustment for amounts already allowed under other provisions, and denial of deduction for certain interest payable outside India where tax compliance conditions are not met.