Summarize the following court judgment. Civil Appeal No. 4139 of 1986. From the Judgment and order dated 18.6.1986 of the Bombay High Court in Appeal No. 874 of 1983. R.P. Bhatt and D.N. Misra for the Appellant. 25 L.C. Chogale	 M.N. Shroff	 K.M.M. Khan	 R.F. Nariman	 R. Karanjawala	 Hardeep Singh	 Mrs. Manek Karanjawala	 S.V. Deshpande	 A.S. Bhasme and A.M. Khanwilkar for the Responlents . The Judgment of the Court was delivered by SEN	 J. By section 127 the Maharashtra Regional & Town Planning Act	 1966 enacts: " 127. If any land reserved	 allotted or designated for any purpose specified in any plan under this Act is not acquired by agreement within ten years from the date on which a final Regional plan	 or final Development plan comes into force or if proceedings for the acquisition of such land under this Act or under the Land Acquisition Act	 1894	 are not commenced within such period	 the owner or any person interested in the land may serve notice on the Planning Authority	 Development Authority or as the case may be	 Appropriate Authority to that effect; and if within six months from the date of the service of such notice	 the land is not acquired or no steps as aforesaid are commenced for its acquisition	 the reservation	 allotment or designation shall be deemed to have lapsed	 and thereupon the land shall be deemed to be released from such reservation	 allotment or designation and shall become available to the owner for the purpose of development or otherwise	 permissible in the case of adjacent land under the relevant plan. " The short point involved in this appeal by special leave from a judgment of a Division Bench of the Bombay High Court dated June 18	 1986	 is whether the period of six months specified in section 127 of the Act is to be reckoned from the date of service of the purchase notice dated July 1	 1977 by the owner on the Planning Authority i.e. the Municipal Corporation of Greater Bombay here	 or the date on which the requisite information of particulars furnished by the owner. The late Dr. Eruchshaw Jamshedji Hakim was the former owner of a double storeyed building situate on land admeasuring 3645.26 square metres bearing the cadastral survey No. 176 of Tardeo	 Bombay known as Dr. Hakimwadi. The property is located at the junction of Falkland Road and Eruchshaw Hakim Road. It 26 consists of several structures housing 24 small scale industries	 13 shops on the ground floor and 26 residential tenements on the first floor	 facing the Falkland Road. On the rear side of this building	 there are several structures housing about 24 small scale industries. The said Dr. Eruchshaw Jamshedji Hakim created a trust in respect of the properties and respondents nos. 6 9 i.e. respondents nos. 4 7 in the High Court	 herein described as such are the present trustees appointed under the deed. The Planning Authority published a draft Development Plan in respect of 'D ' ward where the property in dispute is situate. In the Development Plan property of Dr. Eruchshaw Jamshedji Hakim was reserved for a recreation ground. The Development Plan was finalised and sanctioned by the State Government on January 6	 1967. The final development scheme came into effect from February 7	 1967 and thereunder the land was again reserved for recreation ground. No action having been taken for acquisition of the land until January 1	 1977	 the owners thereof i.e. the trustees served a purchase notice dated July	 1	 1977 on the Commissioner for Municipal Corporation of Greater Bombay either to acquire the same or release it from acquisition	 and the same was received on July 4	 1977. On July 28	 1977 the Corporation 's Executive Engineer wrote to respondents nos. 4 7 and asked for information regarding the ownership of the land and the particulars of the tenants thereof. The letter stated that the relevant date under section 127 of the Act would be the date upon which this information was received. The trustees for the time being the landlords of the property known as Hakimwadi by their lawyer 's letter dated August 3	 1977 conveyed that the date of six months stipulated by section 127 of the Act has to be computed from the date of the receipt from them of the information required. Further	 they stated that as the Planning Authority for Greater Bombay was the Municipal Corporation of Greater Bombay	 it had p access to all the relevant records including the records pertaining to cadastral survey No. 176. It was also appointed out that the Corporation had been assessing them to property tax in respect of the said property and issuing bills and receipts therefor and could not now question their title to ownership of the property. It was further said that as regards the number of tenants	 the inspection registers maintained by the Corporation 's Assessment Department	 upon which the assessment of the rateable value of the various tenements was based	 bear ample testimony. It was next stated that the property was partly residential	 partly commercial and partly meant for storage. The trustees went on to say that they were not aware of any rule framed under the Act whereby the Planning 27 Authority could make an inquiry at that stage without taking a decision on the material question and thereby attempt to extend the time limit of six months stipulated in section 127. The said letter was received by the Executive Engineer on August 16	 1977 and presumably the information required was furnished on August 16	 1977. The Executive Engineer wrote to respondents nos. 4 7 stating that the period of six months allowed by section 127 of the Act would accordingly commence on August 4	 1977	 the date when the requisite information was furnished. Next	 the Executive Engineer by his letter dated November 2	 1977 intimated respondents nos. 4 7 that the Municipal Corporation had accorded sanction to initiate acquisition proceedings in respect of the property in question under the Land Acquisition Act. Thereafter	 the Corporation passed a resolution dated January 10	 1978 for the acquisition of the land and made an application to the State Government dated January 31	 1978 for taking necessary steps. The State Government being satisfied that the land was required for a public purpose issued the requisite notification dated April 7	 1978 under section 6 of the Land Acquisition Act	 1894 for acquisition of the land. On July 17	 1978 respondent No. 1 Dr. Hakimwadi Tenants Association filed a petition in the High Court under article 226 of the Constitution for quashing the impugned notification. A learned Single Judge (Pendse	 J.) by his judgment dated September 21	 1983 allowed the writ petition on the ground that the Planning Authority having taken no steps for acquisition of land under section 126(1) of the Act read with section 6 of the Land Acquisition Act within 10 years from the date on which the final Development Plan came into force	 the acquisition proceedings commenced by the State Government under sub section (2) of section 126 at the instance of the Planning Authority were not valid inasmuch as the issuance of the impugned notification under section 6 of the Land Acquisition Act for the reservation of the property under the final Development Plan for a recreation ground was not within the period of six months as required under section 127. According to the learned Single Judge	 the period of six months prescribed under section 127 of the Act begin to run on the date of service of the purchase notice on the Corporation and therefore the Corporation had to take steps to acquire the property before January 4	 1978. The Corporation not having taken any steps till the expiry of the period of six months	 the resolution dated January 10	 1978 passed to acquire the property and the consequent notification dated April 7	 1978 were invalid and of no legal consequence In other words	 he held that the commencement of the statutory period of six months was not dependent upon the directions issued by the officers 28 of the Planning Authority	 nor could the officers extend the period fixed under section 127. As regards the practice prevalent in the Corporation to compute the period of six months from the date of receipt of the information sought	 he held that it was wholly unwarranted and entirely illegal. He accordingly struck down the impugned notification under section 6 of the Land Acquisition Act and declared that the reservation of the land under the Development Plan had lapsed and it was open to the tenants of the property to claim that due to the lapse of reservation	 the Planning Authority and the State Government had no jurisdiction to acquire the land in exercise of the powers under s.126 of the Act. Aggrieved	 the appellant carried an appeal to a Division Bench under section 15 of the Letters Patent. Bharucha	 J. speaking for himself and Desai	 J. upheld the view of the learned Single Judge and held that the most crucial step was the application to be made by the Corporation to the State Government under section 126(1) of the Act for acquisition of the land	 it ought to have been taken within the period of six months commencing from July 4	 1977	 the date of service of the purchase notice. That decision proceeds upon the view that the details of ownership or particulars of tenants are not required to be furnished in the purchase notice served by the owner or any person interested in the land. All that is required is that the owner or the person interested in the land must inform the authority that the land reserved for any plan under the Act had not been acquired by agreement within 10 years from the date on which the plan came into force and that proceedings for acquisition of such land under the Land Acquisition Act had not been commenced within that period. It was accordingly held that the purchase notice dated July 1	 1977 served by respondents nos. 4 7	 the trustees	 was a valid notice under section 127 of the Act and therefore the period of six months specified in section 127 commenced running from July 4	 1977	 the date of service	 and came to an end on January 4	 1978. That being so	 it was held that upon the expiry of the period of six months on January 3	 1978	 the reservation of the land for recreation ground lapsed and it was released from such reservation. According to the plain reading of section 127 of the Act	 it is manifest that the question whether the reservation has lapsed due to the failure of the Planning Authority to take any steps within a period of six months of the date of service of the notice of purchase as stipulated by section 126	 is a mixed question of fact and law. It would therefore be difficult	 if not well nigh impossible	 to lay down a rule 29 of universal application. It cannot be posited that the period of six months would necessarily begin to run from the date of service of a purchase notice under section 127 of the Act. The condition pre requisite for the running of time under section 127 is the service of a valid purchase notice. It is needless to stress that the Corporation must prima facie be satisfied that the notice served was by the owner of the affected land or any person interested in the land. But	 at the same time	 section 127 of the Act does not contemplate an investigation into title by the officers of the Planning Authority	 nor can the officers prevent the running of time if there is a valid notice. Viewed in that perspective	 the High Court rightly held that the Executive Engineer of the Municipal Corporation was not justified in addressing the letter dated July 29	 1977 by which he required respondents nos. 4 7	 the trustees	 to furnish information regarding their title and ownership	 and also to furnish particulars of the tenants	 the nature and user of the tenements and the total area occupied by them at present. The Corporation had the requisite information in their records. The High Court was therefore right in reaching the conclusion that it did. In the present case	 the Planning Authority was the Municipal Corporation of Greater Bombay. It cannot be doubted that the Municipal Corporation has access to all land records including the records pertaining to cadastral survey No. 176 of Tardeo. We are inclined to the view that the aforesaid letter dated July 28	 1977 addressed by the Executive Engineer was just as attempt to prevent the running of time and was of little or no consequence. As was rightly pointed out by respondents nos. 4 7 in their reply dated August 3	 1977	 there was no question of the period of six months being reckoned from the date of the receipt from them of the information requisitioned. The Municipal Corporation had been assessing the trust properties to property tax and issuing periodic bills and receipts therefor and obviously could not question the title or ownership of the trust. We are informed that the building being situate on Falkland Road	 the occupants are mostly dancing girls and this is in the knowledge of the Corporation authorities. The rateable value of each tenement would also be known by an inspection of the assessment registers. We must accordingly uphold the finding arrived at by the High Court that the appellant having failed to take any steps	 namely	 of making an application to the State Government for acquiring the land under the Land Acquisition Act within a period of six months from the date of service of the purchase notice	 the impugned notification issued by the State Government under section 6 of the Land Acquisition Act making the requisite declaration that such land was required for a public purpose i.e. for a recreation ground was invalid	 null and void. 30 While the contention of learned counsel appearing for the appellant that the words 'six months from the date of service of such notice ' in section 127 of the Act were not susceptible of a literal construction	 must be accepted	 it must be borne in mind that the period of six months provided by section 127 upon the expiry of which the reservation of the land under a Development Plan lapses	 is a valuable safeguard to the citizen against arbitrary and irrational executive action. Section 127 of the Act is a fetter upon the power of eminent domain. By enacting section 127 the legislature has struck a balance between the competing claims of the interests of the general public as regards the rights of an individual. An analysis of section 126 would reveal that after publication of a draft regional plan	 a development or any other plan or town planning scheme	 any land is required or reserved for any of the public purposes specified therein	 the Planning Authority	 Development Authority or as the case may be	 any Appropriate Authority may	 except as provided in section 113A	 at any time acquire the land either by agreement or make an application to the State Government for acquisition of such land under the Land Acquisition Act	 1894. Sub section (2) thereof provides that the State Government may on receipt of the applications contemplated by section 126(1) or if the Government (except in cases falling under section 49 and except as provided in section 113A) is itself of opinion that any land included in any such plan is needed for any public purpose	 it may make a declaration to that effect in the final gazette	 in the manner provided in section 6 of the Land Acquisition Act in respect of the said land. The rule is subject to an exception. Proviso to section 126(2) interdicts that no such declaration shall be made after the expiry of three years from the date of publication of the draft regional plan	 development plan or any other plan. Sub section (3) deals with the procedure to be followed for acquisition of the land covered by a declaration under section 6 of the p Land Acquisition Act. Sub section (4) is of some relevance and reads as follows: "(4). If a declaration is not made within the period referred to in sub section (2) or having been made	 the aforesaid period expired on the commencement of the Maharashtra Regional and Town Planning (Amendment) Act	 1970	 the State Government may make a fresh declaration for acquiring the land under the Land Acquisition Act	 1894	 in the manner provided by sub sections (2) and (3) of this section	 subject to the modification that the market value of the land shall be market value at the date of declaration in the official Gazette made for acquiring the land afresh. " 31 The conjoint effect of sub sections ( 1)	 (2) and (4) of section 126 is that if no declaration is made within the period referred to in sub section (2)	 that is to say	 before the expiry of three years from the date of publication of the draft regional plan	 development plan or any other plan	 the compensation payable to the owner of the land for such acquisition	 in that event	 shall be the market value on the date of the fresh declaration under section 6 of the Land Acquisition Act i.e. the market value not at the date of the notification under section 4(1) of the Land Acquisition Act but the market value at the date of declaration under section 6. That is one of the safeguards provided under the Act. Another safeguard provided is the one under section 127 of the Act. It cannot be laid down as an abstract proposition that the period of six months would always begin to run from the date of service of notice. The Corporation is entitled to be satisfied that the purchase notice under section 127 of the Act has been served by the owner or any person interested in the land. If there is no such notice by the owner or any person	 there is no question of the reservation	 allotment or designation of the land under a development plan of having lapsed. It a fortiori follows that in the absence of a valid notice under section 127	 there is no question of the land becoming available to the owner for the purpose of development or otherwise. In the present case	 these considerations do not arise. We must hold in agreement with the High Court that the purchase notice dated July 1	 1977 served by respondents nos. 4 7 was valid notice and therefore the failure of the appellant to take any steps for the acquisition of the land within the period of six months therefrom	 the reservation of the land in the Development Plan for a recreation ground lapsed and consequently	 the impugned notification dated April 7	 1978 under section 6 of the Land Acquisition Act issued by the State Government must be struck down as a nullity. Section 127 of the Act is a part of the law for acquisition of lands required for public purposes	 namely	 for implementation of schemes of town planning. The statutory bar created by section 127 providing that reservation of land under a development scheme shall lapse if no steps are taken for acquisition of land within a period of six months from the date of service of the purchase notice	 is an integral part of the machinery created by which acquisition of land takes place. The word 'aforesaid ' in the collocation of the words 'no steps as aforesaid are commenced for its acquisition ' obviously refer to the steps contemplated by section 126(1). The effect of a declaration by the State Government under sub section (2) thereof	 if it is satisfied that the 32 land is required for the implementation of a regional plan	 development plan or any other town planning scheme	 followed by the requisite declaration to that effect in the official gazette	 in the manner provided by section 6 of the Land Acquisition Act	 is to freeze the prices of the lands affected. The Act lays down the principles of fixation by providing firstly	 by the proviso to section 126(2) that no such declaration under sub section (2) shall be made after the expiry of three years from the date of publication of the draft regional plan	 development plan or any other plan	 secondly	 by enacting sub section (4) of section 126 that if a declaration is not made within the period referred to in sub section (2)	 the State Government may make a fresh declaration but	 in that event	 the market value of the land shall be the market value at the date of the declaration under section 6 and not the market value at the date of the notification under section 4	 and thirdly	 by section 127 that if any land reserved	 allotted or designated for any purpose in any development plan is not acquired by agreement within 10 years from the date on which a final regional plan or development plan comes into force or if proceedings for the acquisition of such land under the Land Acquisition Act are not commenced within such period	 such land shall be deemed to be released from such reservation	 allotment or designation and become available to the owner for the purpose of development on the failure of the Appropriate Authority to initiate any steps for its acquisition within a period of six months from the date of service of a notice by the owner or any person interested in the land. It cannot be doubted that a period of 10 years is long enough. The Development or the Planning Authority must take recourse to acquisition with some amount of promptitude in order that the compensation paid to the expropriated owner bears a just relation to the real value of the land as otherwise	 the compensation paid for the acquisition would be wholly illusory. Such fetter on statutory powers is in the interest of the general public and the conditions subject to which they can be exercised must be strictly followed. There still remain the other two points raised	 namely	 (i) There was waiver or abandonment of right by respondents nos. 4 7	 the trustees	 to question the validity of the acquisition proceedings; and (ii) There was inordinate delay or laches on the part of respondent No. 1 which disentitled it to grant of relief under article 226 of the Constitution. We find it difficult to give effect to these contentions. In order to deal with these questions	 a few facts are to be stated. The Executive Engineer of the Municipal Corporation by his letter dated November 2	 1977 addressed to the lawyer acting on be 33 half of respondents nos. 4 7	 the trustees	 to inquire whether they were prepared to sell the property in question situate at Cadastral Survey No. 176 of Taradeo. In response thereto	 respondents nos. 4 7 through their lawyer 's reply dated November 18	 1977 intimated that they were prepared to consider the sale of the property in its existing condition with all the structures tenanted or otherwise at an overall rate of Rs.650 per square metre. This response was without prejudice and they expressly stated that the offer was made without admitting the power and authority of the appellant to acquire the land or to initiate the proceedings for acquisition. Instead of accepting the same	 the Executive Engineer by his letter dated January 11	 1978 wanted respondents nos. 4 7 to disclose the basis upon which they claimed price at the rate of Rs.650 per square metre. While keeping respondents nos. 4 7 in suspense	 the Municipal Corporation had in the meanwhile on January 10	 1978 passed a Resolution that necessary steps be taken to move the State Government for acquisition of the land and thereafter actually moved the Government by their letter dated January 31	 1978 to make the requisite declaration under section 6 of the Land Acquisition Act	 1894 i.e. the property in question was needed for	 public purpose viz. a recreation ground under the Development Plan. The State Government accordingly on April 7	 1978 on being satisfied that the property was needed issued the requisite impugned notification under section 6 of the Act. Thereafter	 the Special Land Acquisition officer on January 18	 1979 issued a general notice under section 9 of the Land Acquisition Act and the same was published at the site and also issued individual notices to the persons interested. The hearing was fixed for February 26	 1979. On February 22	 1979 i.e. four days before the hearing some of the tenants approached the Special Land Acquisition officer and applied for three months ' adjournment and accordingly the bearing was adjourned to April 24	 1979. However	 no claims for compensation were filed. Nobody remained present at the hearing. Accordingly	 the Special Land Acquisition officer was constrained to issue fresh notices under section 9 on May 25	 1981. Thereafter	 the Municipal Corporation on the date fixed applied to the Special Land Acquisition officer to keep the proceedings in abeyance at the behest of some of the tenants who had applied to the Corporation for three months ' time. In the circumstances	 respondents nos. 4 7 moved the High Court under article 226 of the Constitution for a writ in the nature of mandamus requiring the Special Land Acquisition officer to make an award. On January 20	 1981	 the learned Government Advocate gave an undertaking before the High Court that the Special Land Acquisition officer would declare the award within a period of six months 34 and make payment of compensation within eight months. In view of this	 the High Court dismissed the writ petition as not pressed. On these facts	 it cannot be said that there was any waiver or abandonment of rights by respondents nos. In order to constitute waiver	 there must be voluntary and intentional relinquishment of a right. The essence of a waiver is an estoppel and where there is no estoppel	 there is no waiver. Estoppel and waiver are questions of conduct and must necessarily be determined on the facts of each case. In the present case	 respondents nos. 4 7 had without admitting that the appellant had the authority or power to initiate the proceedings for acquisition	 signified their willingness to sell the property subject to certain terms. But the appellant did not accept the offer. On the contrary	 the appellant took further steps for the acquisition of the land by moving the State Government under section 126(1) of the Act to initiate acquisition proceedings by the issuance of a notification under section 6 of the land Acquisition Act. In view of this	 it cannot be said that the conduct of respondents nos. 4 7 was such as warrants an inference of relinquishment by a known existing legal right. There is no question of estoppel	 waiver or abandonment. There is no specific plea of waiver	 acquiescence or estoppel	 much less a plea of abandonment of right. That apart	 the question of waiver really does not arise in the case. Admittedly	 the tenants were not parties to the earlier proceedings. There is	 therefore	 no question of waiver of rights by respondents nos. 4 7 not would this disentitle the tenants from maintaining the writ petition. The objection that there was undue delay in moving the High Court cannot prevail. The reservation has lapsed	 acquisition upon such reservation is bad and the delay in filing the petition	 such as it is	 can make no difference to this position in law. In the result	 the appeal fails and is dismissed with costs. P.S.S. Appeal dismissed.

% Section 127 of the Maharashtra Regional and Town Planning Act	 1966 provides that if any land reserved under the Act was not acquired by agreement within ten years from the date on which a final regional plan or final development plan came into force or if proceedings for the acquisition of such land under that Act or under the Land Acquisition Act	 1894 were not commenced within such period	 the owner or any person interested in the land may serve notice on the appropriate authority to that effect and if within six months from the date of the service of such notice	 the land was not acquired or no steps as aforesaid were commenced for its acquisition	 the reservation should be deemed to have lapsed. The Planning Authority	 the Municipal Corporation of Greater Bombay	 published a draft development plan reserving the land in dispute for a recreation ground. The said plan was finalised and sanctioned by the State Government on January 6	 1967. It came into effect from February 7	 1967 and thereunder the land was again reserved for recreation ground. No action having been taken for acquisition of the land	 the trustees of the land served a notice dated July 1	 1977 on the Commissioner for Municipal Corporation either to acquire the land or release it from acquisition. The same was received by the latter on July 4	 1977. On July 28	 1977 the Corporation 's Executive Engineer asked for information regarding the ownership of the land and the particulars of the tenants thereof from trustees respondents Nos. 4 7	 and stated that the relevant date under section 127 cf the Act would be the date 22 upon which this information was received. The trustees by their lawyer 's letter dated August 3	 1977 conveyed that the period of six months stipulated by section 127 has to be computed from the date of the receipt of the purchase notice by the Corporation	 i.e. July 4	 1977 and stated that the Corporation had access to all the relevant records. The requisite information was also provided therein. The Executive Engineer wrote stating that the period of six months allowed by section 127 of the Act would commence on August 4	 1977	 the date when the requisite information was furnished. Thereafter the Executive Engineer by his letter dated November 2	 1977 inquired of the trustees whether they were prepared to sell the property in question to which the trustees quoted an overall rate of Rs.650 per square metre through their lawyer 's reply dated November 18	 1977. They expressly stated that the offer was made without admitting the power and authority of the appellant to acquire the land or to initiate the proceedings for acquisition. Instead of accepting the same	 the Executive Engineer by his letter dated January 11	 1978 asked the respondents to disclose the basis for the rate of Rs.650 per sq. metre. The Corporation had	 in the meanwhile passed a resolution on January 10	 1978 for the acquisition of the land and made an application to the State Government dated January 31	 1978 for taking necessary steps. The State Government issued the requisite notification dated April 7	 1978 under section 6 of the Land Acquisition Act 1894 for acquisition of land. On July 17	 1978	 respondent No. 1	 the tenants ' association	 filed a petition in the High Court under article 226 of the Constitution for quashing the impugned notification. The High Court held that the most crucial step was the application to be made by the Corporation to the State Government under section 126(1) of the Act for acquisition of the land within the period of six months commencing from July 4	 1977	 the date of service of the purchase notice	 and that upon the expiry of the said period on January 3	 1978	 the reservation of the land had lapsed and it was released from such reservation. It took the view that all that was required was that the owner or the person interested in the land must inform the Authority that the land reserved for any plan under the Act had not been acquired by agreement within ten years from the date on which plan came into force and the proceedings for acquisition of such land under the Land Acquisition Act had not been commenced within that period. Consequently it struck down the impugned notification as invalid	 null and void. In the appeal to this Court by special leave it was contended that there was waiver or abandonment of right by respondents Nos. 4 7	 23 the trustees	 to question the validity of the acquisition proceedings	 and that there was inordinate delay or laches on the part of respondent No. 1 which disentitled it to grant of relief under article 226 of the Constitution. Dismissing the appeal	 ^ HELD: 1. Section 127 of the Maharashtra Regional and Town Planning Act	 1966 is a fetter upon the power of eminent domain. By enacting it the legislature has struck a balance between the competing claims of the interests of the general public as regards the rights of an individual. [30B C] 2. The condition pre requisite for the running of time under 127 of the Act is the service of a valid purchase notice. In the instant case	 the purchase notice dated July 1	 1977 was a valid notice. The appellant having failed to take any steps for acquisition of the land within a period of six months therefrom the reservation of the land in the development plan for a public purpose lapsed and consequently the impugned notification dated April 7	 1978 issued by the State Government under section 6 of the Land Acquisition Act must be struck down as a nullity. [29A B; 31D F] 3.1 The question whether the reservation has lapsed due to the failure of the planning authority to take any steps within a period of six months of the date of service of the notice of purchase as stipulated by section 127 is a mixed question of fact and law. A rule of universal application cannot	 therefore	 be laid down. [28G H] In the instant case the High Court found that the planning authority had failed to acquire the land reserved for the plan under the Act by agreement within ten years from the date on which the plan came into force and proceedings for acquisition of the land under the Land Acquisition Act had not been commenced within the period of six months from the receipt of notice from respondents Nos. 4 to 7	 the trustees. The Municipal Corporation had been assessing the trust properties to property tax and issuing periodic bills and receipts therefor and obviously could not question the title or ownership of the trust. Accordingly	 it struck down the impugned notification under section 6 of the Land Acquisition Act and declared that the reservation of the land under the development plan had lapsed. [28E	 29F	 28B] 3.2 There was no question of the period of six months being 24 reckoned from the date of receipt from respondents of the information requisitioned. Section 127 of the Act does not contemplate an investigation into the title by the officers of the Planning Authority	 nor can the officers prevent the running of time if there is a valid notice. The Executive Engineer of the appellant Corporation was not justified in addressing the letter dated July 28	 1977 calling upon respondents 13 Nos. 4 7	 the trustees	 to furnish information regarding their title and ownership	 and also to furnish particulars of the tenants	 the nature of user of the tenements and the total area occupied by them. The Corporation had the requisite information in their records. The Planning Authority was the Municipal Corporation. The said letter was	 therefore	 just an attempt to prevent the running of time and was of little or no consequence.[29A	 B E] 4. In order to constitute waiver	 there must be voluntary and intentional relinquishment of a right. The essence of a waiver is an estoppel and where there is no estoppel	 there is no waiver. Estoppel and waiver are questions of conduct and must necessarily be determined on the facts of each case. [34B] In the instant case	 respondents Nos. 4 7 had without admitting that the appellant had the authority or power to initiate the proceedings for acquisition	 signified their willingness to sell the property subject to certain terms. But the appellant did not accept the offer. On the contrary	 the appellant took further steps for the acquisition of the land by moving the State Government under section 126(1) of the Act to initiate acquisition proceedings by the issuance of a notification under section 6 of the Land Acquisition Act. It cannot	 therefore	 be said that the conduct of respondents Nos. 4 7 was such as warrants an inference of relinquishment of a known existing legal right. [34B D] 5. The tenants were not parties to the earlier proceedings. They were	 therefore	 not disentitled from maintaining the writ petition. The objection that there was undue delay in moving the High Court cannot prevail. [34E F]