(iv)action by an enemy or action taken in combating an enemy (whether with or without a declaration of war), and, thereafter, at any time before the expiry of three years from the end of such previous year, the business is re-established, reconstructed or revived by the assessee, he shall, in respect of the previous year in which the business is so re-established, reconstructed or revived, be allowed a deduction of a sum by way of rehabilitation allowance equivalent to sixty per cent. of the amount of the deduction allowable to him under clause (iii) of sub-section (1) of section 32 in respect of the building, machinery, plant or furniture so damaged or destroyed:]
