In order to file an e-TDS Return, the payer/ deductor needs to attach Challan Status Inquiry (CSI) file for that Quarter. You can download the Challan Status Inquiry (CSI) from OLTAS.
Following are the two ways to download it:
CIN Based: Using BSR Code of Collecting Branch, Challan Paid on Date & Challan Serial No. and amount (optional).
TAN Based: Using TAN and Challan Paid on Date.
Read More: How to download CSI file?