V.S. SIRPURKAR, J.

This judgment shall govern and dispose of two writ petitions, which were initially filed in the Gujarat High Court and originally registered as Special Civil Application Nos.3282 and 3279 of 1989. While Spl.C.A. No.3282 of 1989 was filed by Adani Exports Limited, Spl.C.A. No.3279 of 1989 was filed by one Inter Continental (India), a partnership firm.

2. Both these Special Civil Appeals as they were filed before the Gujarat High Court were allowed by the High Court by a common judgment dated 3-4-2000 and 17-2-2000. This judgment was challenged before the Apex Court by the Union of India, respondents herein vide Civil Appeal Nos.6320 and 6321 of 2000. The Apex Court allowed these appeals only on the ground of 'territorial jurisdiction'. Following is the operative part of the judgment:

"For the reasons stated above, these appeals succeed and the same are hereby allowed. The impugned judgment is set aside. We further direct that Special Civil Application Nos.3282/99 and 3279/99 filed by the respondents are hereby directed to be transferred to the High Court of Madras at Chennai forthwith and on receipt of the papers, we request the Chief Justice of the High Court of Madras to place them before an appropriate Bench for disposal in accordance with law. We are also of the opinion that since the parties have already undergone one round of litigation before the High Court at Ahmedabad and thereafter in these appeals before us, it is appropriate to request the High Court to dispose of these appeals as early as possible. The appeals are, accordingly, allowed."

In pursuance of the above direction, the matters were sent to this Court which were re-registered as W.P. Nos.4320 and 4321 of 2002 and have now been placed before us for disposal by the Hon'ble Chief Justice.

3. Though the controversy involved in these writ petitions is extremely narrow, the factual background is somewhat spread out. Fortunately, the factual background in both the writ petitions is practically identical and hence, we propose to dispose of these writ petitions by a common judgment as was done by the Gujarat High Court.

4. After seeing the pleadings of the parties in writ petitions and the counters filed on behalf of Union of India, the controversy revolves around only one question, viz.:

"Whether the petitioners are entitled to avail credit of the customs duties under the 'passbook' scheme on the basis of the import contents of exports already made based on Standard Input/Output Norms, referred to as 'SION' hereafter, prevailing upto 31-3-1997 or whether such credit would be governed by the subsequent SION applicable to the parties starting from 1-4-1997 which are in respect of other duty exemption schemes other than the passbook scheme?"

The question may still be compressed further to the effect:

"whether the petitioners are entitled to the credit of customs duties in respect of Vitamin Mixes and Mineral Mixes at the rate of 227 Kg. for every metric ton of headless/head-on shrimps already exported by them as per SION prevailing in between 1st April 1992 and 31st March 1997 or the same should be restricted to only 27 Kgs. as per SION for the period beginning from 1st April 1997?"

A still third question on the basis of the arguments raised before us by the learned Additional Solicitor General is to the effect as to:

"Whether without proving the actual prior imports of Vitamin Mixes and Mineral Mixes can the petitioners claim the credit of customs duties at all on the basis of their exports of head-on/headless shrimps?"

5. For appreciating the controversies involved, the following undisputed factual details would be essential:

5.1 Both the petitioners are exporters and enjoying the status of 'Super Star Trading House' in the State of Gujarat on account of their quantum of exports. They are major foreign exchange earners.

5.2 Union of India and the other respondents, under the powers conferred upon them by the provisions of Foreign Trade (Development