petitioner before us, urges that there was no justification for making the benefits available under the subject two DFIAs, as originally issued, to the various conditionalities and limitations subsequently introduced by the impugned Notifications, Circular and Public Notice, which were never in existence on the date of issuance of the DFIAs themselves. Additionally, he has emphasised the impossibility of compliance with the conditions stipulated in the impugned Notifications, Circular and Public Notice, which require specifications to be inserted in the Shipping Bills whereunder the exports, in fulfilment of Export Obligation, are made and, further, imports, only of such items, to be effected, as were used in the manufacture of the export product, irrespective of the SION norms. He submits that, where the exports were made prior to issuance of the DFIAs themselves, it is obviously impossible for the importer, importing goods thereafter, to limit the imports to the goods used in the product already exported, or to use the same in export goods, and stresses the absurdity of such a stipulation. In fine, the learned Senior Counsel re-emphasises that the DFIAs originally issued to the Exporter and subsequently transferred to the petitioner, could only be subjected to the conditions existing in the FTP, HOP and in the instructions issued by the DGFT in this regard, on or before the date of issuance of the DFIAs. DFIAs issued prior to 01/08/2013, in other words, could not, according to the learned Senior Counsel, be subjected to conditions and limitations which came into being thereafter, in the impugned Notifications/Circular/Public Notice. The doctrine of promissory estoppel is also pressed into service, in this regard.