Summarize the following court judgment. il Appeals Nos. 751 of 1957 and 10 of 1958. Appeal from the judgment and order dated December 7	 1956	 of the Calcutta High Court in Matters Nos. 29 and 58 of 1956. M. C. Setalvad	 Attorney General of India	 C. K. Daphtary	 Solicitor General of India	 Sukumar Mitra	 Sankar Ghosh and B. N. Ghosh	 for the appellants in C. A. No 751 of 57. M. C. Setalvad	 Attorney General of India	 Sankar Ghosh and D. N. Mukherjee	 for the appellants in C. A. No. 10 of 1958. section M. Bose	 Advocate Generalfor the State of West 905 Bengal	 B. Sen and P. K. Bose	 for the respondents (in both the appeals). 1960. September 27. The Judgment of the Court was delivered by HIDAYATULLAH J. These two appeals on a certificate under article 132(1) of the Constitution have been filed respectively by the Burmah Shell Oil Storage land Distributing Co.	 of India	 Ltd.	 and the Standard Vacuum Oil Company (in this judgment referred to as the appellant Companies) against a common judgment of the High Court of Calcutta dated December 7	 1956. The High Court was moved for writs of mandamus	 prohibition and certiorari under article 226	 but the petition was dismissed by D. N. Sinha	 J. The matter arises out of assessment to sales tax on sale of motor spirit for aviation purposes (shortly	 aviation spirit) supplied by the appellant Companies to aircraft bound for countries abroad	 under the Bengal Motor Spirit Sales Taxation Act	 1941	 as amended by section 2(a)(i) of the Bengal Motor Spirit Sales Taxation (Second Amendment) Act	 1954. The Commercial Tax Officer	 the Commissioner of Commercial Taxes and the State of West Bengal have been joined as respondents in this Court	 as they had previously been joined in the High Court. The appellant Companies deal in Petroleum and Petroleum products	 and carry on business at Calcutta. They maintain supply depots at Dum Dum Airport from which aviation spirit is sold and delivered to aircraft proceeding abroad and belonging to several Companies. It appears that such sales were treated by the sales tax authorities in the State of Bombay as not falling within the taxing Acts in force in the Bombay State by reason of the provisions of article 286 of the Constitution. The sales tax authorities in West Bengal	 however	 took a different view of the matter	 and after sundry procedure resulting in assessment of tax	 presented a demand notice for the tax assessed which was paid under protest by the appellant Companies. The appellant Companies filed petitions under article 226 of the Constitution in the High 906 Court of Calcutta questioning the legality of the imposition but without success. They have now filed these appeals after obtaining a certificate	 as already stated. The contentions in this Court	 as they were also before the High Court	 'are that such sales are made in the course of export of such aviation spirit out of the territory of India	 that they take place outside the State of West Bengal	 that inasmuch as aviation spirit is delivered for consumption outside West Bengal	 the sales cannot fall within the Explanation to sub cl. (a) of the first clause of article 286	 and that unless they can be said to become "Explanation Sales"	 the power to tax does not exist. It is argued in support of the last contention that there is not even an averment in the reply of the respondents before the High Court that aviation spirit is delivered for consumption within West Bengal. The case in the High Court was restricted to consideration of supplies to aircraft which either proceed to foreign countries directly from Dum Dum Airport	 or do so ultimately	 though landing en route at some place or places in the Indian territory. The case has been similarly confined in this Court also	 and we are not required to express any opinion about sales of aviation spirit to aircraft flying from one place in West Bengal to another place also within that State	 or even to some place in another State in the territory of India. The facts are fortunately not ' in dispute. Both parties admitted the procedure for the supply of aviation spirit to aircraft. Briefly described	 it is as follows: Before the arrival of such an aircraft	 a representative of the appellant Companies applies to the Airport Customs Officer to depute an Officer to supervise the refuelling of the aircraft. After the aircraft lands	 the captain or the Ground Engineer gives instruction about the quantity of aviation spirit required	 and on permission being given by the Customs authorities	 the stated quantity is delivered in the presence of the Customs Officer deputed. Details of the delivery are entered in a delivery receipt	 which 907 is signed by the representative of the appellant Companies and the Customs Officer deputed. Duty drawback shipping bills are also drawn up to show the ' quantity of aviation spirit and are countersigned by them and also by a representative of the aircraft. Later	 claims for refund of customs duty are made	 and refund is granted. In the petition filed in the High Court	 it was averred that such aviation spirit is required for consumption during flight and/or outside the territory of India	 and is thus delivered for purposes of consumption outside West Bengal and in some cases outside the territorial limits of India as well. It was also stated that it was sold in the course of export outside the territory of India	 and drawback of customs duty was obtained. In the reply of the respondents	 it was stated that the refund of customs duty was an irrele vant fact for the purpose of assessment. It was further stated in the affidavit of the Commercial Tax Officer as follows : " I further state that a foreign bound aircraft on leaving Dum Dum Airport consumes a portion of the aviation spirit taken in by it at the Airport within the territory of West Bengal before it moves out of the said territory or the territory of India. I do not admit that the entire quantity is used outside the territorial limits of India as alleged. I deny that the sale of such aviation spirit takes place outside the State of West Bengal and state that the sale takes place within the State of West Bengal and the purchaser pays its price within the State of West Bengal. The sale of such aviation spirit is completed by delivery at the Dum Dum Airport in West Bengal. " We have mentioned this fact	 because it was argued that the respondents had not averred clearly that aviation spirit was sold for consumption within West Bengal even though the appellant Companies had denied it. The respondents pointed out that at least some of the aviation spirit must be consumed in the State	 and that this was so stated in the affidavit filed in reply to the petition and quoted by us. This is 908 hardly a case for a fight on pleadings	 especially as the entire procedure of the supply of aviation spirit and the use to which it is put are beyond controversy. The question that we have to consider is one of principle	 and the answer depends upon broad facts and not on technicalities. Either the whole of the sale is within the taxing power of the State or it is not	 and the fact that aviation spirit is consumed in taking off or in flying over the territory of West Bengal before it leaves that territory would make no difference either way to the principles applicable. Though parties entered into a debate on this part of the case	 we do not propose to consider it	 because	 in our opinion	 the question must be considered in substance and not in abstractions. The liability to sales tax	 if any	 is attracted when aviation spirit is sold	 and immunity can only be claimed	 if	 as stated in article 286(1)(a) and the Explanation	 the sale can be said to take place outside the State or can be regarded under article 286(1)(b) as having taken place " in the course of. export of the goods out of	 the territory of India". Before we take up these two questions	 we desire to refer to some provisions of certain Acts	 which bear upon the matter. The Indian 	 is an Act for the control of the manufacture	 possession	 use	 operation	 sale	 import and export of aircraft. Section 16 of this Act provides that the Central Government may	 by notification in the Official Gazette	 declare that any or all of the provisions of the Sea Customs Act shall	 with such modifications and adaptations as may be specified in the notification	 apply to the import and export of goods by air Sections 2(3) and (4) define " import" and " export ' respectively as " bringing into India " and " taking out of India ". A notification issued under the Indian 	 the rules framed thereunder and the Indian Aircraft Rules	 1920	 appointed the Civil Aerodrome	 Dum Dum	 a Customs Aerodrome	 and to that Customs Aerodrome	 the provisions of the Sea Customs Act mutatis mutandis were made applicable by r. 63 (Part IX) of the Indian Aircraft Rules	 1920. As 909 a result	 Dum Dum Airport became a Customs Aerodrome	 and any aircraft coming into India from foreign countries or leaving for any such country has to comply with ordinary Customs formalities. Section 42 of the Sea Customs Act	 which allows drawback on re export and is applicable mutatis mutandis	 provides: " When any goods	 capable of being easily identified	 which have been imported by sea into any customs port from any foreign port	 and upon which duties of customs have been paid on importation	 are re exported by sea from such customs port to any foreign port	 or as provisions or stores for use on board a ship proceeding to a foreign port seven eighths. of such duties shall	 except as otherwise hereinafter provided	 be repaid as drawback: ". (Provisos omitted). Under section 51	 no drawback is allowed unless the claim to receive such drawback is made and established at the time of re export	 and under section 52	 the person claiming drawback has to make and subscribe to a declaration. The procedure which is described in an earlier portion of this judgment bears upon these matters. Coming now to the taxing Acts with which we are concerned	 it may be pointed out that the Bengal Motor Spirit Sales Taxation Act	 1941	 originally did not contemplate levy of a tax on the sale of aviation spirit. Motor spirit was defined to mean	 " any liquid or admixture of liquids which is ordinarily used directly or indirectly as fuel for any form of motor vehicle or stationary internal combustion engine	 and which has a flashing point below 76 degrees Fahrenheit ". Sub section (4) of section 3	 which is the charging section	 provided that no tax shall be levied on the sale of any motor spirit for the purpose of aviation. The Act was amended by the Second Amendment Act	 1954	 and sub section (4) of section 3 was omitted	 and the proviso to the first sub section was re enacted	 adding one more clause to the following effect 910 the tax on all retail sales of motor spirit for the purpose of aviation	 which are effected on or after the date of the commencement of the Bengal Motor Spirit Sales Taxation (Second Amendment) Act	 1954	 shall be charged at the rate of three annas per gallon ". By the Bengal Motor Spirit Sales Taxation (Amendment) Act	 1955	 the original Act was further amended. To the definition of" motor spirit ' quoted by us earlier	 an Explanation was retrospectively added	 which reads as follows: " Explanation For the avoidance of doubt	 it is hereby declared that in this Act	 the expression ' vehicle ' means any means of carriage	 conveyance or transport	 by land	 air or water ". The original Act was again amended by the Bengal Motor Spirit Sales Taxation (Amendment) Act	 1957. This time	 among other amendments involving rates of tax	 the words " and which has a flashing point below 76 degrees Fahrenheit " were omitted from the definition of 'motor spirit '. The result of all these amendments was to make retail sales of aviation spirit liable to sales tax	 and 'retail sale ' was defined	 at all material times	 as a sale " by a retail dealer for the purpose of consumption by the purchaser ". After the coming into force of the Constitution	 section 22	 in terms of article 286	 was added to the original Act by paragraph 3 of	 and the Eleventh Schedule to	 the Adaptation of Laws Order	 1950. It read: " 22(1). Nothing in this Act shall be construed to impose or authorise the imposition of a tax on the sale or purchase of motor spirit: (a) where the sale or purchase takes place outside the State of West Bengal; (b) where the sale or purchase takes place in the course of the import of such motor spirit into	 or export of such motor spirit out of the territory of India; or (c) (omitted). (2) The Explanation to clause (1) of article 286 of the Constitution shall apply for the interpretation of clause (a) of sub section (1) 911 Clauses (a) and (b) of the first sub section do no more than re enact the prohibition contained in article 286 of the Constitution with modifications to Suit motor spirit	 and the Explanation to sub cl. (a) of cl. (1) of the said Article in the Constitution has been applied without an attempt to modify or adopt it. The Explanation to sub cl. (a) of the first clause of article 286	 the meaning of which was much in dispute in this case	 may conveniently be quoted here. It reads: " Explanation For the purposes of sub clause (a)	 a sale or purchase shall be deemed to have taken place in the State in which the goods have actually been delivered as a direct result of such sale or purchase for the purpose of consumption in that State	 notwithstanding the fact that under the general laws relating to sale of goods the property in the goods has by reason of such sale or purchase passed in another State ". The High Court of Calcutta in its judgment dealt with the points urged	 and rejected them. The reasons of the High Court briefly were as follows: The learned Judge declined to draw any inference from the fact that customs duties were refunded as drawbacks on aviation spirit delivered to the aircraft. He held that he was not required to decide whether the appellant Companies were entitled to claim and receive drawbacks of customs duty. He then gave a finding that the sale was physically within the State	 because both the buyer and the purchaser were	 at the time of sale	 within the State of West Bengal even though delivery of aviation spirit was beyond the customs barrier. He then considered the legal position in the light of article 286 from three points of view. He first held that it was not an inter State transaction	 because both the parties were in the State of West Bengal	 and aviation spirit was not delivered outside the State. Thus	 he held that el. (2) of article 286 did not apply. In this connection	 he relied upon the decision of this Court in the Bengal Immunity Co.	 Ltd. vs State of Bihar and others (1). He next considered (1) 912 the matter under the first sub clause	 and held that unless the fiction created by the Explanation applied	 the sale must be treated as within the State under the law relating to sale of goods. In his opinion	 the sale being completed within the State of West Bengal both as regards contract and delivery	 the fiction could not be held applicable	 because no " outside " State was involved	 even though the aircraft might have to consume some aviation spirit while flying over the " outside " State. He	 therefore	 held that the Explanation and article 286(1)(a) which it seeks to explain	 were both not applicable. He then considered the matter from the point of view of article 286(1)(b). He explained on the authority of the decision of this Court in State Of Travancore Cochin and others vs Shanmugha Vilas Cashewnut Factory and others (2) that the expression " in the course of export out of the territory of India" referred to sales which	 by themselves	 occasioned the export of goods out of the territory of India and not to sales for the purpose of export	 even though the goods ultimately passed the customs barrier. He pointed out that there was no foreign purchaser to whom the aviation spirit could be said to have been exported	 and that aviation spirit	 in fact	 was consumed en route and never taken to any foreign territory. He also pointed out that no bills of lading or shipping documents were drawn up	 and therefore there was neither an export nor a sale in the course of export out of the territory of India. The appellant Companies claim that these sales come within the exemption granted the sub cls. (a) and (b) of the first clause of article 286. To claim the exemption granted by the first sub clause	 they rely upon certain decisions of this Court	 and contend that unless the sale can be said to fall within the Explanation	 it must be treated as a sale outside the State of West Bengal	 and is thus exempt. With regard to the second sub clause	 they contend that there was an export out of the territory of India inasmuch as aviation spirit was taken abroad and any sale by which it is taken abroad is also exempt These (2) ; 913 arguments	 as has been shown above	 were urged before the High Court	 but were not accepted. These two arguments need to be considered separately	 as they have little in common. Article 286 places restrictions upon the power of the States to tax sales and purchase of goods	 and cuts down the amplitude of Entry No. 54 in the Second List of the Seventh Schedule. Other restrictions are also to be found in Part XIII of the Constitution. With those we are not concerned in these appeals. We are also not concerned with the subsequent amendment of article 286	 nor with the ban imposed by the second clause of the Article on taxes on sales in the course of inter State trade and commerce. We are concerned with the first clause only	 as it stood before the amendment. That clause is divided into two sub clauses. The first sub clause prohibits the imposition of tax on the sale or purchase of goods where the sale or purchase takes place outside the State. AD Explanation is added to this sub clause	 which has been quoted by us earlier. This Explanation has led to a long controversy in this Court during which somewhat conflicting views have been expressed about its meaning. This conflict has further been accentuated when the interplay between the two clauses has been considered. The view now accepted is that the bans imposed by the two clauses are independent and separate and each must separately be got over. In view of this	 we are not required to travel beyond the first clause in this case. We have heard widely divergent arguments in these appeals. The learned Attorney General who appeared on behalf of the appellant Companies read to us copious extracts from the earlier decisions of this Court	 and contended that unless the sales could be said to fall within the Explanation so as to become 'Explanation sales '	 they must be regarded as having taken place outside the State of West Bengal and for that reason	 not taxable. According to him	 they could only become 'Explanation sales ' if aviation spirit was delivered for the purpose of consumption within the State of West Bengal. The learned Advocate General of West Bengal	 on the other band	 914 contended that the Explanation did not apply to the facts here	 and that the observations in the rulings were not relevant. The first sub clause in its opening portion says that no law of a State shall impose or authorise the imposition of a tax on the sale or purchase of goods where such sale or purchase takes place outside the State. It is thus plainly meant that a State is not to tax sales which take place outside that State. But	 where does a sale take place ? Numerous elements go to make a sale	 and they may take place in more than one State. Under the law relating to the sale of goods	 property passes on the happening of certain events. When they happen	 the sale is complete. Now	 a contract for the sale of goods may be entirely within one State when all parties are within the State	 the offer and acceptance also take place there	 and the goods are also within that State	 and there	 the property in the goods passes and delivery also takes place. But it may also happen that the constituent elements may be spread over two or more States	 some of the elements described above falling within one State and some others falling within one or more other States. Prior to the Constitution	 multiple taxation of a single transaction of sale was possible	 and Provincial legislation then existing clearly demonstrates that States having Some connection with the sale because one or more elements took place within those States	 treated this as sufficient nexus between the taxing power and the States	 authorising them to tax sales even where property passed in another State. The Constituent Assembly desired to achieve certain objects in the matter of taxation	 particularly in relation to sales tax. Article 286 achieves	 among other objects	 the avoidance of this multiple taxation. The first sub clause of the Article is clear in its terms	 when it says that a State cannot tax sales which take place outside the State. The converse is also true	 that is to say	 that a State can tax a sale of goods which takes place within the State. By sale here is meant a completed transaction by which property in the goods passes. Before the property in the 915 goods passes	 the contract of sale is only executory	 and the buyer has only a chose in action. " Property in the goods passes either by the fulfilment of the conditions of the contract	 if any	 or by the operation of the law relating to the sale of goods. Starting from the basic fact that what is to be taxed under the Constitution is a sale completed by the transference of property in the goods	 we have to see at what stage and where this happens. The taxable event thus cannot be found at any earlier stage when the sale is not completed by the passing of property. The critical taxable event is the passing of property in the goods as a result of a contract for their sale. The parties to the contract can agree when that event is to take place	 but where it happens may be a matter of some doubt and even of difficulty. Where the parties have not agreed as to the time of the passing of property	 the law relating to the sale of goods furnishes the answer. There too	 there may be the same difficulty as to the place of the passing of property. The place of physical delivery of the goods does not help to solve this difficulty	 because delivery may	 precede or follow the passing of property in the goods. Delivery of goods is	 thus	 not always an element which determines the completion of a sale	 because the sale may be completed both before and after delivery. The Constitution	 however	 thinks in. ' terms of a completed sale by the passing of property and not in terms of an executory contract for the sale of goods. The essence of the matter being thus the passing of property in goods		 there was always a likelihood of more than one State claiming the right to tax the same transaction. One State might claim that goods in which property passed were in that State	 and hence property in the goods passed there. Another State might claim that the conditions precedent to the passing of property were fulfilled in that State and hence the sale was completed by the passing of property there. Yet another State might claim that property passed in that State according as one or more events connected with the passing of property took place within that State. 916 It was to avoid this welter of confusion as far as possible that the Explanation was added	 and it also avoided multiple taxation. The Explanation serves two purposes. It indicates the State where the tax can be levied	 and also indicates the State or States where it cannot. It achieves these two purposes excluding all considerations as to where property the goods can be said to have passed under the law relating to the sale of goods. The purpose is achieved by the Explanation and particularly by the non obstante clause in the Explanation. Any State claiming to tax a sale of goods on the ground that it was completed by the passing of property in the goods in that State could not do so	 if the goods as a direct result of the sale were delivered for the purpose of consumption in another State. The Explanation creates a fiction that the sale must be deemed to have taken place in the latter State and not in the State where the sale was completed by reason of passing of property. It thus discards the test of passing of property and adopts the test of delivery 'as a direct result of such sale for the purpose of consumption in that State '. Where more than one State is involved	 any State claiming to tax the sale by reason of something anterior to the passing of property would not be able to claim that the sale took place there unless it was also the State of delivery	 because the sale is complete only on the passing Of property	 and till the sale is complete	 liability to tax does not arise. Once the sale is complete	 the delivery State gets the right to tax the sale by the fiction introduced. Now	 the Explanation must be ' interpreted according to its own tenor	 and it is meant to explain el. (1)(a) of the Article and not vice versa. It is an error to explain the Explanation with the aid of the Article	 because this reverses their roles. The Explanation discards the test of passing of property	 and adopts the test of delivery as a direct result of the sale for purposes of consumption. This delivery may be in the State where the passing of property also took place	 but then	 there is no difficulty. The sale is then entirely within the State. The sale is outside 917 the State only when the passing of property takes place in the State	 but that is not the State where the goods have been actually delivered as a direct result of the sale for purposes of consumption in that State. The Constitution has	 thus	 for certain cases shifted and confined the situs of the taxable event to the State of the delivery of goods; but it must be remembered that this delivery	may precede as well as follow the passing of property. It is	 therefore	 plain that no single element of the contract of sale is by itself a decisive factor in determining which State is to tax the sale where there are more States than one involved	 except the test of actual delivery of the goods in a State as a direct result of the sale for purposes of consumption in that State	 and it is that State and that State only which has the right to tax the sale and none other. The Explanation is not applicable	 unless there are more States than one involved. It is only a key to find out which of the States is competent to tax and which are not	 and is by no means a definition of an 'outside sale '. It is an Explanation	 which determines which State out of those connected with the transaction of sale can tax it. The interpretation which we have placed upon the first sub clause of article 286(1) is substantially the same	 as was placed in the earlier rulings of this Court. In The State of Bombay and another vs The United Motors (India) Ltd. and others (1)	 it was pointed out that the Explanation formulated an easily applicable test to find out an 'outside sale ' and this	 it was said	 was done " by defining an inside sale ". It was observed further: " Are the goods actually delivered in the taxing State	 as a direct result of a sale or purchase	 for the purpose of consumption therein ? Then	 such sale or purchase shall be deemed to have taken place in that State and outside all other States ". Certain reasons were given why this test was adopted	 and it is these reasons and their effect on the second clause	 which led to a re examination of the subclause in The Bengal Immunity Company Limited vs (1) ; 117 918 The State of Bihar and others (1). The majority in that case touched upon the various grounds which were advanced before this Court	 but declined to express "any final opinion upon the matter ". The case went on to decide that the bans imposed by the two clauses of article 286 were independent	 and needed to be separately enforced. But	 on the meaning of the Explanation	 no different view was expressed. Again	 in M/8. Ramnarain Sons Ltd. vs Asst. Commissioner of Sales Tax and others(2)	 it was observed as follows: "So far as article 286(1)(a) is concerned	 the Explanation determines by the legal fiction created therein the situs of the sale in the case of transactions coming within that category and when a transaction is thus determined to be inside a particular State it necessarily becomes a transaction outside all other States. The only relevant enquiry for the purposes of article 286(1)(a)	 therefore	 is whether a transaction is outside the State and once it is determined by the application of the Explanation that it is outside the State it follows as a matter of course that the State with reference to which the transaction can thus be predicated to be outside it can never tax the transaction (Italics supplied). Now	 in so far as this case is concerned	 the words the Explanation determines by the legal fiction created therein the situs of the sale in the case of transactions coming within that category " in the extract last quoted	 become important. The first question to consider is whether these cases can be governed by the Explanation at all. The learned Attorney General contends that the power to tax these transactions can only be found if the sales were 'Explanation sales '	 in the sense that the goods were delivered as a direct result of the sale for consumption in West Bengal. In our opinion	 the explanation can apply only if more than one State is involved in the same transaction. When there is no other State in which the goods can be said to be delivered for consumption	 apart from the State where the property in the goods passed	 the Explanation is not needed as a key. The (1) (2) ; 492. 919 power to tax in those circumstances which is exercisable by virtue of transfer of title to the property	 can only be taken away if there be some other State in ' which the goods as a direct result of the sale were delivered for consumption. But if there is no such other State	 the question does not arise. In the present cases	 there is no such rival State. Where the purchaser buys goods in West Bengal for his own consumption	 the test of an 'inside sale ' is satisfied when the property in the goods passes in the same State and all the elements of the contract of sale also take place inside it. Where the property in the goods passes to a buyer who is also the 'ultimate 	consumer	 the terms of the Explanation are themselves satisfied. To exclude	 thus	 the powers of taxation of the State of West Bengal	 the appellant Companies must be able to point out some other State where the goods can be said to have been delivered as a direct result of the sale for the purpose of consumption in that other State. Unless they can do so and they have not so done before us they cannot invoke the Explanation	 and the cases	 to borrow the language of the last quotation	 cannot be said to be "within that category ". In our opinion	 the learned Advocate General of West Bengal was right in his argument (which was accepted by the High Court) that the ban contained in article 286(1)(a) and the Explanation does not apply. The appellant Companies next rely upon article 286 (1)(b)	 which provides that: " No law of a State shall impose or authorise the imposition of	 a tax on the sale or purchase of goods where such sale or purchase takes place in the course of the. . export of goods out of	 the territory of India ". The contention is that the sales in question must be regarded as having taken place in circumstances which exempt sales under the sub clause. This the appellant Companies argue from the following facts that aviation spirit is delivered outside the customs barrier	 that aviation spirit is taken out of the territories of India	 and that the sales occasion this 920 export. They rely upon the definition of 'export ' in other Acts to show that the word means no more than 'taking out of the country '. This clause of the Article has been construed on previous occasions by this Court	 and what is meant by the expression " in the course of " has been well. established. Indeed	 in State of Mysore vs Mysore Spinning and Manufacturing Co. Ltd. (1)	 this Court observed that the point could no longer be said to be at large. Fortunately	 there is less disagreement on this point than on the interpretation of the Explanation	 and it is sufficient to refer to the leading decisions of this Court. The earliest case on the subject is State of Travancore Cochin and others vs The Bombay Co. Ltd. (2)	 where four possible meanings of the expression " in the course of " were considered. It is not necessary to refer to all of them here	 and it is sufficient to point out that of the view that the clause is not restricted to the point of time at which goods are exported from India and that the series of transactions which necesssarily precede export of goods also come within the purview of the clause	 it was said that it was too wide. It was observed by this Court that: "A sale by export thus involves a series of integrated activities commencing from the agreement of sale with a foreign buyer and ending with the delivery of the goods to a common carrier for transport out of the country by land or sea. Such a sale cannot be dissociated from the export without which ' it cannot be effectuated	 and the sale and resultant export form parts of a single transaction. Of these two integrated activities	 which together constitute an export sale	 whichever first occurs can well be regarded as taking place in the course of the other. " The meaning of these observations was further explained in State of Travancore Cochin and others vs Shanmugha Vilas Cashew Nut Factory and Others (3). It was observed (p. 62) that the words "export out of " in this context did not refer to the article or commodity exported	 and that the reference to "the (1) A.I.R. 1958 section C. 1002. (2) ; (3) ; 921 goods " and to the "territory of India " made it clear that the words " export out of " meant the exportation out of the country. It was then added that	 "The word 'course ' etymologically denotes movement from one point to another	 and the expression 'in the course of ' not only implies a period of time during which the movement is in progress but postulates also a connected relation. " This inter connection of the sale sought to be taxed with the course of export was emphasised again in clear terms thus : " The phrase 'integrated activities ' was used in the previous decision to denote that 'such sale ' (i.e.	 a sale which occasions the export) I cannot be dissociated from the export without which it cannot be effectuated	 and the sale and the resultant export form parts of a single transaction '. It is in that sense that the two activities the sale and export were said to be integrated. A purchase for the purpose of export like production or manufacture for export	 is only an act preparatory to export and cannot	 in our opinion	 be regarded as an act done I in the course of the export of the goods out of the territory of India ' any more than the other two activities can be so regarded. " From the views here expressed	 it follows that every sale or purchase preceding the export is not necessarily to be regarded as within the course of export. It must be inextricably bound up with the export	 and a sale or purchase unconnected with the ultimate export as an integral part thereof is not within the exemption. It may thus be taken as settled that sales or purchases for the purpose of export are not protected	 unless the sales or purchases themselves occasion the export and are an integral part of it. The views expressed in these two cases were accepted and applied in State of Madras vs Gurviah Naidu and Co. Ltd. (1)	 Kailash Nath vs State of U.P. (2)	 State of Mysore vs Mysore Spinning and Manufacturing Co. Ltd. (3) and Gordhandas Lalji vs B. Banerjee (1) A.I.R. 1956 S.C. 158. (2) A.I.R. 1057 S.C. 790. (3) A.I.R. 1958 S.C. 1002. 922 and others (1). These cases do not advance the matter further	 and it is	 therefore	 not necessary to refer to them in detail. In the earlier cases	 it was not necessary to explain the meaning of the word 'export '	 because there was always a foreign buyer to whom the goods were ultimately sent. In none of the cases the facts found here were present. Here	 the buyer does not export the goods to a foreign country	 but purchases them for his own use on the journey of the aircraft to foreign countries. This difference is vital	 and makes the position of the appellant Companies	 if anything	 weaker. It is for this reason that the appellant Companies depend on a wide meaning of the word 'export '	 which they illustrate from other Acts where the word is tantamount to "taking out of the country '. We are of opinion that this meaning cannot be given to the word 'export ' in the clause. The word 'export ' may conceivably be used in more senses than one. In one sense	 'export ' may mean sending or taking out of the country	 but in another sense	 it may mean sending goods from one country to another. Often		 the latter involves a commercial transaction but not necessarily. The country to which the goods are thus sent is said to import them	 and the words 'export ' and import ' in this sense are complementary. An illustration will express this difference vividly. Goods cannot be said to be exported if they are ordered by the health authorities to be destroyed by dumping them in the sea	 and for that purpose are taken out of the territories of India and beyond the territorial waters and dumped in the open sea. Conversely	 goods put on board a steamer bound for a foreign country but jettisoned can still be said to have been exported '	 even though they do not reach their destination. In the one case	 there is no export	 and in the other	 there is	 though in either case the goods go to the bottom of the sea. The first would not be within the exemption even if a sale was involved	 while any sale in the course of the second taking out would be. In both	 the goods were taken out of the country. The difference lies in (1) A.I.R. 1958 S.C. 1006. 923 the fact that whereas the goods	 in the first example	 had no foreign destination	 the goods	 in the second example	 had. It means	 therefore	 that while all exports involve a taking out of the country	 all goods taken out of the country cannot be said to be exported. The test is that the goods must have a foreign destination where they can be said to be imported. It matters not that there is no valuable consideration from the receiver at the destination end. If the goods are ex. ported and there is sale or purchase in the course of that export and the sale or purchase occasions the export to a foreign destination	 the exemption is earn. Purchases made by philanthropists of goods in the course of export to foreign countries to alleviate distress there	 may still be exempted	 even though the sending of the goods was a not a commercial venture but a charitable one. The crucial fact is the sending of the goods to a foreign destination where they would be received as imports. The two notions of export and import	 thus	 go in pairs. Applying these several tests to the cases on hand	 it is quite plain that aviation spirit loaded on board an aircraft for consumption	 though taken out of the country	 is not exported since it has no destination where it can be said to be imported	 and so long as it does not satisfy this test	 it cannot be said that the sale was in the course of export. Further	 as has already been pointed out	 the sales can hardly be said to 'occasion ' the export. The seller sells aviation spirit for the use of the aircraft	 and the sale is not integrally connected with the taking out of aviation spirit. The sale is not even for the purpose of export	 as explained above. It does not come within the course of export	 which requires an even deeper relation. The sales	 thus	 do not come within article 286 (1)(b). These sales must	 therefore	 be treated as made within the State of West Bengal. The customs barrier is a barrier for customs purposes	 and duty drawback may be admissible if the goods once imported are taken out of the country. The customs duty drawbacks have nothing to do with the sale of aviation 924 spirit	 which takes place in West Bengal. The cus toms barrier does not set a terminal limit to the territory of West Bengal for sales tax purposes. The sale beyond the customs barrier is still a sale	 in fact	 in the State of West Bengal. Both the buyer and the seller are in that State. The goods are also there. All the elements of sale including delivery	 payment of price	 take place within the State. The sale is thus completely within the territory of the taxing State. No outside State is involved where the goods can be said to have been delivered for consumption as a direct result of the sale that takes place. Article 286(1)(a) and the Explanation are wholly inapplicable	 and the sale cannot	 even by a fiction	 be said to be outside the State of West Bengal. No doubt	 aviation spirit is taken out of the State and also the territory of India	 but it cannot be said to have been exported or delivered for consumption in some other State. The so called export is not occasioned by the sale	 and the sale	 on the authorities cited	 is not in the course of export '	 so as to attract article 286(1)(b). The decision of the High Court was correct. The appeals fail	 and are dismissed with costs. One hearing fee. Appeal dismissed.

The appellant companies which were carrying on business in Calcutta in petroleum and petroleum products maintained supply depots at Dum Dum Airport from which motor spirit for B the purposes of aviation was sold and delivered to aircraft which either proceeded to foreign countries directly from that Airport or did so ultimately	 though landing en route at some place or places in the Indian territory. Dum Dum Airport was a customs aerodrome and all aircraft coming into it or leaving it had to comply with ordinary customs formalities. The sales tax authorities of West Bengal sought to levy tax on the sales of motor spirit as aforesaid under the provisions of the Bengal Motor Spirit Sales Taxation Act	 1941	 as amended. The appellant companies claimed that the sales were exempted from taxation under both the clauses (a) and (b) of article 286(i) of the Constitution of India on the grounds (i) that the sales in question had taken place outside the State of West Bengal	 as they did not .come within the Explanation to article 286(1)(a)	 (2) that aviation spirit was delivered outside the customs barrier and therefore the sales were outside the State	 and (3) that the sales had taken place in the course of export	 as aviation spirit was taken out of the territory of India. Held: (i) that by sale in article 286(i)(a) is meant a completed transaction by which property in the goods passes. Before property in the goods passes the contract of sale is only executory and the buyer has only a chose in action. The taxable event is not to be found at an earlier stage because the critical taxable event is the passing of property. The Explanation to cl. (1) of article 286 was added to avoid	 among other things	 multiple taxation of the same transaction. It indicates the State where the tax can be levied and also the State where it cannot. It achieves it by excluding from consideration the place where the property in the goods passed according to the law relating to sale of goods. The non obstante clause establishes this. By the fiction created by the Explanation a sale is deemed to have taken place in the State where the goods are delivered as a direct result of the sale for purposes of consumption in that State. Where there are more States than one involved	 any State claiming to tax a sale by reason of something anterior to the passing of property would not be able to claim that the sale took place there unless it was also the State of delivery. The Explanation is meant to explain the Article and must be interpreted according to its tenor and the Explanation is not to be explained with the aid of the Article because that would reverse their roles. The Explanation is not applicable unless there are more States than one involved. The State of Bombay vs The United Motors (India) Ltd.	 	 State of Travancore Cochin vs Shanmugha Vilas Cashewnut Factory	 ; 	 Ramnayain Sons Ltd. vs Asst. 904 Commissioner of Sales Tax; 	 and The Bengal Immunity Company Ltd. vs The State of Bihar	 [1955] 2 S.C.P. 603	 considered. (2) that to exclude the power of taxation of the State of West Bengal under article 286(i)(a)	 read with the Explanation	 the appellant companies must be able to point out some other State where the goods could be said to have been delivered as a result of the sale for the purpose of consumption in that other State	 and that where	 as in the present case	 aviation spirit was delivered to the aircraft	 there was no such rival State	 and therefore	 the ban contained in article 286(i)(a) and the Explanation	 did not apply. (3) that in the phrase " in the course of export out of the territory of India " in article 286(i)(b) the word " export " does not merely mean 'taking out of the country '. Export here means that the goods are being sent to a foreign destination at which the goods can be said to be imported. In the Article the notions of import and export go in pairs. State of Travancore Cockin vs The Bombay Co. Ltd.	 ; and State of Travancore Cochin vs Shanmugha Vilas Cashew Nut Factory	 ; 	 relied on. (4) that aviation spirit loaded on board the aircraft for consumption	 though taken out of the country	 was not exported since it had no destination where it could be said to be imported. The sales in question could not	 therefore	 be said to have occasioned the export	 nor were they in the course of export. Accordingly	 article 286(i)(b) was not applicable. (5) that the sales must be treated as made within the State of West Bengal. The customs barrier did not set a terminal limit to the territory of West Bengal for the purposes of sales tax	 and the sales	 though beyond the customs barrier	 were still within the territory of the taxing State.