Retention money was to be taxed when it became payable to contractor as per terms of construction co

IT: Where assessee was awarded a construction contract and in terms of contract certain amount was withheld by employer of contract towards retention money for satisfactory execution of contract by assessee, retention money was to be taxed in assessment year relevant to 'previous year' in which it became payable to assessee as per terms of contract ie., after defect liability was over and after engineer-in-charge certified that no liability was attached to aassessee