Tax deduction at source required from designated government payers; remittance, certification, ledger credit and refund rules apply. Designated government entities and notified persons must withhold tax at the prescribed rate on taxable supplies above a specified threshold, excluding tax components shown on the invoice; deductors must remit withheld amounts within the prescribed period, issue prescribed certificates to deductees, and face late fees for delayed certification and interest for non-payment. Deductees claim credit in their electronic cash ledger as reflected in the deductor's return; defaults and refunds for excess or erroneous deductions follow statutory procedures, and refunds to deductors are barred if the amount has been credited to the deductee's electronic cash ledger.