Tax deduction at source on salaries requires employers to deduct tax at average rates on estimated salary income. Payers of income chargeable under Salaries must deduct tax at source at the average rate on the assessee's estimated salary for the financial year. Payers may opt to pay tax on certain non-monetary perquisites as if deductible at source, and eligible start-ups have special timing rules for deduction or payment of tax on specified securities or sweat equity perquisites. Employees with multiple employments or entitled to salary-relief may furnish prescribed particulars for use in computing TDS, and payers must adjust deductions for prior excesses or deficiencies and apply prescribed conversions for foreign-currency salary.