Deemed defective return under section 139(9): unpaid self-assessment tax on e-filing requires notice and corrected upload. Unpaid self-assessment tax at e-filing renders the return a deemed defective return under section 139(9); CPC will identify such returns, issue notices requiring payment and upload of corrected returns via the e-filing 'response to notice' facility (with CPC reference/password where applicable), suppressing acknowledgment generation until corrected returns with payment details are received. CPC will forward monthly lists of unrectified cases to jurisdictional AOs for follow-up, and Directorate of Systems will refresh case lists periodically after removals for rectified returns.