Tax deduction at source: government-mandated withholding from supplier payments when contract value exceeds prescribed threshold, with credit and compliance rules. Government may require specified public bodies and notified persons to deduct tax at source from supplier payments above a prescribed contract value, using invoice value exclusive of central, State, integrated tax and cess. Deductors must remit withheld amounts within the prescribed period, issue certificates to deductees detailing contract value and amounts withheld, and face prescribed late fees for failure to issue certificates, interest for failure to remit, and specified procedures for claiming electronic cash ledger credit and for determination of defaults and refunds.