Additional depreciation allowance for new machinery grants an extra half-share deduction in the year of installation. The amendment inserts clause (iia) into section 32(1) to provide an additional depreciation allowance equal to one-half of the amount admissible under clause (ii) for specified new machinery or plant in the year of installation or, if first used in the succeeding year, for that year, excluding extra shift-working allowances and hotel-installation allowances. Deductions are prohibited for machinery in office or residential premises, for office appliances or road transport vehicles, and for assets whose entire cost is deductible in one year; subsection (2) is amended to refer to clause (iia).