Tax deduction at source requires specified government entities to withhold tax from supplier payments exceeding prescribed thresholds and remit timely. Mandated tax deduction at source requires specified government entities and notified persons to withhold tax from payments to suppliers of taxable goods or services above the prescribed threshold, excluding central tax, State tax, integrated tax and cess from the value. The deductor must remit withheld amounts within ten days after month end and provide the deductee a certificate of deduction; failure to furnish the certificate triggers a daily late fee. The deductee may claim credit in the electronic cash ledger as reflected in the deductor's return; interest and statutory default determination apply where withheld amounts are not paid, and refunds are governed by the statutory refund mechanism.