Depreciation rate for plant and machinery ( residuary categery ) is 15 % .since this air compressor falls on others categery this is qualified for 15 % depreciation.
with regarding to additional depreciation if an assesee acquires and put to use a new plant and machinery for production or manufacturing of article or thing ,then assesee qualifies for additional depreciation. But that p&m should be new, should not be used for residential purpose,should not be used as office appliance, shouldnot be used for personal purpose, shouldnot be motor vehicles, shouldnot be an aeroplane and ship. if that investment in p& m is made in notified backward areas in specified states of Andhra, westbengal, Bihar and telangana then assessee is entitled to add dep of 35% others - 20 %