This instruction lays down comprehensive guidelines for exercising powers under Rule 86A to restrict debit of input tax credit from the electronic credit ledger. It clarifies that such power can be exercised only when the Commissioner or an authorised officer has recorded “reasons to believe” that ITC has been fraudulently availed or is ineligible, based on specified statutory grounds. The instruction emphasises that the power is extraordinary and must not be exercised mechanically, but with due application of mind and supporting material evidence. Monetary limits are prescribed for officers of different ranks competent to invoke Rule 86A. The restriction must be proportionate and limited to the amount of suspected ineligible ITC. It also provides for review, release of blocked credit where conditions no longer exist, and automatic lapse of restriction after one year, while directing expeditious completion of investigation and adjudication.