How to compute actual rent while computing gross annual value of a property which is let-out throughout the year?

Actual rent: vacancy not deductible; unrealised rent deductible only if tenancy is bona fide and recovery steps taken.

Actual rent is the rent for which the property is let during the year and rent for vacancy periods is not deductible. Unrealised rent-rent not recovered from the tenant-may be deducted from actual rent only if the tenancy is bona fide; the defaulting tenant has vacated or steps have been taken to compel vacation; the defaulting tenant does not occupy any other property of the taxpayer; and the owner has pursued all steps to recover the amount or demonstrates to the Assessing Officer that legal proceedings would be useless.