TDS on contractor payments requires tax deduction at source on payments or credits to contractors under specified conditions. Section 194C mandates deduction of tax at source on payments to contractors and sub-contractors for carrying out works, including supply of labour, at the time of credit or payment; crediting to any account, including suspense accounts, is deemed payment. Deductions depend on payee status and invoice treatment of material, with exemptions for personal payments by individuals and HUFs, de minimis thresholds subject to an annual aggregate override, and special reliefs and declaration requirements for certain goods carriage operators.