A classification of goods made on the basis of certain general principles cannot be changed unless some change in circumstances has taken place or a decision of a superior authority or a judicial pronouncement has come into existence subsequent thereto.

This writ petition can be disposed of on a very short ground. The petitioners are manufacturing among other things, flavouring essences for edible food products. Notification No. 55/75-C.E., dated 1-3-1975 exempted certain goods specified in the Schedule and falling under Item No. 68 of the First Schedule to the Central Excises and Salt Act, 1944 from the whole of the duty of excise leviable thereon. The first item mentioned therein is `all kinds of food products and food preparations' including six items specified therein. It is not necessary for me to refer to those items which are included. It is sufficient to note that all kinds of food products are exempted under the notification.

2.By Letter dated 11-8-1975 in C. No. V/68/30/21/75, the Assistant Collector of Central Excise, Madras IV Division issued a notice to the petitioners to show cause why flavouring essences for edible food products should not be classified as non-food products assessable to duty under Item No. 68 of the C.E. Tariff. The Assistant Collector rejected the contention of the petitioners that they would fall under the expression `food products' and passed an order. The petitioners filed an appeal before the Appellate Collector of Customs and Central Excise. By order dated 6-4-1978 in Appeal No. 578/78, the Appellate Authority held that the flavouring essences in question for edible food products will fall within the meaning of Notification No. 55/75, dated 1-3-1975 and therefore exempt from duty under Item No. 68 of the Central Excise Tariff.

3.That decision became final as it was not challenged in any manner. When the petitioner submitted a classification list in the next year bearing No. 92/78 that was approved by the Superintendent of Central Excise on the basis of the order passed by the Appellate Authority referred to earlier. In the next year the classification list No. 39/79 was filed by the petitioners as required by the rules. As against the relevant entry referring to flavouring essences for edible food products (non-alcoholic), the list stated that they were exempted under the notification. The petitioners also referred to the order of the Appellate Collector in Appeal No. 578/78 dated 6-4-1978. However, the Superintendent of Central Excise did not choose to accept their claim for exemption and made an endorsement at the bottom of the list that the said items are excisable and tariff classification and rate of duty are leviable in respect of those goods. He sent a memorandum, which is marked as Annexure VII along with the said classification list, para 2 of the said memorandum reads thus:

"Flavouring Essences for edible food products (non-alcoholic) and `Flavouring Essences (Alcoholic)' shown in Item No. 5 and Sl. No. 1 and 4 of your classification list respectively are classified as the Excisable items. In this connection your kind attention is invited on this office Letter O.C. No. 74/80 dated 18-1-1980. Clearance of the above said items should be made after payment of Central Excise Duty under Tariff item No. 68. Receipt of this letter may please be acknowledged."

4.In spite of the fact that the order was against the petitioners herein, the Collector of Central Excise chose to issue a show cause notice under Section 35A of the Act on 26-6-1980 to the petitioners to show cause why the classification made by the Superintendent should not be set aside the goods should not be treated as excisable. Obviously the Collector was under the impression that the Superintendent's endorsement was in favour of the petitioners herein. He has overlooked that the Superintendent had only held against the petitioners if at all. After the petitioners made their representation a detailed order was passed by the Collector on 22-9-1980 holding that the products in question are not food or food products and they are liable for duty. The last part of the said order reads as follows :-

"For the reasons mentioned in para 16 above, I order that flavouring ess