Depreciation deductions for business assets restricted by usage, asset type, and succession rules, with additional allowance for new machinery. Deduction is allowed for depreciation of tangible and qualifying intangible assets used wholly and exclusively for business or profession, computed at prescribed rates on written down value for blocks of assets; part use is restricted to a proportionate deduction. Additional first year deduction is available for new machinery or plant in manufacturing or power businesses subject to novelty, installation, use and location conditions, with reduced allowance where assets are used for less than a specified period in the year. Succession, amalgamation and demerger entitlements are capped and apportioned pro rata, and capital works on leased buildings are treated as owned for depreciation.