TAN or Tax Deduction Account Number is a 10 digit alphanumeric number required for all persons responsible for deducting or collecting tax. It must be quoted in all TDS/TCS returns, payment challans, and certificates. Failure to apply for a TAN or comply with related provisions carries a penalty of Rs. 10,000. Different branches/divisions of a company may apply for separate TANs, but a person cannot have or use more than one TAN.