Deduction for operating expenditure clarifies permissible business expense categories and exclusions, and timing for payment-based claims. Clause 33 defines operating expenditure as the aggregate of specified business expenditures and specified deductions subject to conditions. It lists admissible items-raw materials, rent, current repairs, maintenance, salaries, insurance premiums, selling and promotional costs limited to amounts charged to profit and loss, employee welfare and training, R&D costs, approved fund contributions, head office allocation for non residents, acquisition costs on reorganisation or transfer when sold as trading assets, protection of goodwill, taxes actually paid, encashment of leave and gratuity actually paid-and permits certain deductions like opening inventory and prescribed bad debt provisions. It excludes personal, capital, finance charges, unascertained liabilities, political advertising, wealth tax, taxes on profits and dividends. Certain items are deductible only when paid or when the liability arises.