It is necessary to quote the TAN in all TDS/TCS returns along with all of the challans of TDS/TCS payment and the certificates of TDS/TCS to be issued. The returns of TDS/TCS will not be established if TAN is not quoted. Also, the challans for TDS/TCS payments will not be acknowledged by the banks. In fact if someone fails to apply for TAN or does not quote the same in the stated documents, then he would be liable to pay a penalty of Rs. 10,000/-. The requirements of section 203A of the Income-tax Act necessitate all individuals who subtract or gather tax at the source to get the allotment of a TAN done.