The Central Board of Direct Taxes (CBDT) has launched a computer-generated documentation identification number (DIN) system which provides for a transparent and recorded communication between the income tax department and taxpayers. A DIN will be mandatory for every type of communication with the income tax department, be it a notice, a letter, an order and summon, or any other correspondence. Without it, the document and communication will be deemed invalid, said a CBDT statement. “From now onwards (October 1), every CBDT communication will be required to have a documentation identification number. The system would ensure greater accountability and transparency in tax administration,” finance minister Nirmala Sitharaman had tweeted. On Tuesday, the first day of operation, 17,500 DINs were issued, the statement said. Revenue secretary Ajay Bhushan Pandey said, “Any communication from income tax department without a computer-generated DIN will be invalid.”