JUDGMENT R.S. Pathak, J. - a statement of a case referred to this Court under Sec. 24(2) of the U.P. Agricultural Income Tax Act for its opinion on the following questions :- (i) Was the notice of June 14, 1954 asking the assessee to file a return next day in accordance with the provisions of Sec. 25 of the U.P. Agricultural Income Tax Act? (ii) Was the assessment illegal on account of the defect in the notice, if any? (iii) Did the filing of the return as directed in the notice amount to a waiver of any defect in the notice? 2. Proceedings for the assessment of the petitioner for the assessment year 1361F. were taken, and it was held that he was not liable to assessment, the taxable income being below the limit mentioned in Sec. 4 of the Act. Subsequently, upon assessment proceedings being completed for the assessment year 1360F, it was found that certain further income was liable to be assessed in the hands of the assessee for 1361F. A notice, purporting to be under Sec. 25 of the Act, was issued on June 14, 1954 calling upon the assessee to appear on the next day and to submit a return. An assessment order under Sec. 25 was made on June 20, 1955. An appeal preferred by the assessee against the assessment was dismissed. The assessee then filed a revision application, contending that the notice under Sec. 25 was invalid as it did not allow him a period of at least 30 days for filing his return, but the Revision Board held that assuming the notice was defective the assessee had waived any objection to the invalidity of the notice by actually filing a return within the time specified in the notice. Sec. 25 provides: "If for any reason any agricultural income chargeable to agricultural income tax has escaped assessment for any year or has been assessed at too low a rate, the assessing authority may, at any time within two years of the expiry of that year serve on the person liable to pay agricultural income tax on such agricultural income . . . . . a notice containing all or any of the requirements which may be included in a notice under sub-Sec. (3) of Sec. 15 and may upon service of such notice proceed to assess or re-assess such income, and the provisions of this Act, shall, so far as may, apply accordingly as if the notice was a notice issued under that sub-section." Sec. 15(3) empowers the assessing authority to serve "a notice in the prescribed form requiring such person to furnish within such period, not being less than thirty days as may be specified in the notice, a return in the prescribed form and verified in the prescribed manner . . .". 3. Question No. 1 calls for a decision on the point whether the notice of June 14, 1954 requiring the assessee to file a return the next day satisfies the provisions of Sec. 25. For the assessee it is contended that the notice under Sec. 25 must contain the requirements which may be included in a notice under Sec. 15(3), and that one of these requirements essential to the validity of the notice is that it must specify a period not less than thirty days for filing the return, and since this period has not been specified, the notice is not a notice in accordance with Sec. 25. 4. Learned counsel for the State, however, urges that the specification of the period for furnishing the return is not a requirement which must be included in the notice, that a notice which does not mention the time within which the return must be filed is not a notice wanting in any of the requirements contemplated by the statute, and, therefore, the provision in the notice for filing the return the next day, though less than the period provided by the statute, nevertheless does not invalidate the notice. He submits that all that the law requires is the issue of a notice calling for a return, and if the notice satisfies that condition it is a notice valid in law. 5. We are unable to accept the contention advanced on behalf of the State. The notice under Sec. 25 must contain the requirements which may be included in a notice under Sec. 15(3). The notice under Sec. 15(3) requires an assessee to furnish a return. The requisition does not stop there. It proceeds further, and, indeed, must proceed further. 5. We are unable to accept the contention advanced on behalf of the State. The notice under Sec. 25 must contain the requirements which may be included in a notice under Sec. 15(3). The notice under Sec. 15(3) requires an assessee to furnish a return. The requisition does not stop there. It proceeds further, and, indeed, must proceed further. It requires the assessee to furnish a return within certain period. It appears to us that unless the period for furnishing the return is specified in the notice, it is an incomplete notice. The very object of the Act, which is a fiscal statute, indicates that the assessment should be completed within a definite period and, therefore, it is necessary that the assessee should be required to file a return within a specified period. An assessee who fails without reasonable cause or excuse to furnish a return in due time is liable to penalty under Sec. 37. The enactment of Sec. 37 testifies to the intention of the legislature that the return is required to be filed within a definite period, and accordingly a duty is cast upon the assessing authority to specify such period in the notice calling for the return. The notice must not merely require an assessee to furnish a return. It must require an assessee to furnish a return within a specified period, that period being not less than thirty days. It is only then a notice containing the requirements of Sec. 15(3). 6. The notice issued on July 14, 1954 requiring the assessee to file a return on the next day is not a notice containing the requirements of a notice under Sec. 15(3) and, therefore, it is not a notice issued in accordance with the provisions of Sec. 25 of the Act. Our answer to question No. 1 is, therefore, in the negative. 7. It is well settled that a notice seeking to initiate proceedings for the assessment of income which has escaped assessment or has been assessed at too low a rate is a jurisdictional notice. The issue of the notice is a condition precedent to the assumption of jurisdiction for assessing such income. See Commissioner of Income Tax v. Ramsukh Motilal, (1955) 27 I.T.R. 54 . The issue of the notice is a condition precedent to the assumption of jurisdiction for assessing such income. See Commissioner of Income Tax v. Ramsukh Motilal, (1955) 27 I.T.R. 54 . If an assessee has been assessed, the assessment proceedings become final, and he is entitled not to have his assessment disturbed unless the conditions of Sec. 25 are satisfied. Similarly, if an assessee has not been assessed at all, and the period within which he should have been so assessed has lapsed, it is not open to the assessing authority to take assessment proceedings unless recourse be had to Sec. 25. That it is not open to an assessing authority to initiate assessment proceedings after a certain period without recourse to provisions such as Sec. 25, is now concluded by the decision in Commissioner of Income Tax v. Narsee Nagsee, A.I.R. 1960 S.C. 1232. Since one of the conditions which must be satisfied before jurisdiction is assumed for assessing income which has escaped assessment or has been assessed at too low a rate is the issue of a valid notice under Sec. 25, an assessment consequent to an invalid notice must be held to be bad in law. Inasmuch as the notice of June 14, 1954 was invalid, the assessment made against the assessee on June 20, 1955 must be held to be illegal. Our answer to question No. 2 is, therefore, in the affirmative. 8. Question No. 3 raises the point whether the filing of the return by the assessee in accordance with the direction contained in the notice amounts to a waiver of any defect in the notice. It was strenuously contended by learned counsel for the assessee that an objection to the validity of the notice under Sec. 25 cannot be waived, while it was contended with equal vehemence on behalf of the State that such objection could be waived. In our judgment, it does not appear necessary to decide the question whether an objection to the notice under Sec. 25 could or could not be waived. It is sufficient to point out that there are no facts before us upon which it can be held in law that there was any waiver. The mere filing of a return as directed by the notice does not in itself establish that the assessee had waived his right to object to the notice. In Manak Lal v. Dr. It is sufficient to point out that there are no facts before us upon which it can be held in law that there was any waiver. The mere filing of a return as directed by the notice does not in itself establish that the assessee had waived his right to object to the notice. In Manak Lal v. Dr. Prem Chand, A.I.R. 1957 S.C. 425 the Supreme Court observed that "Waiver can be inferred only if and after it is shown that the party knew about the relevant facts and was aware of his right to take the objection in question and again in Basheshar Nath v. I.T. Commissioner, A.I.R. 1959 S.C. 149. "The generally accepted connotation is that to constitute "waiver" there must be an intentional relinquishment of a known right or the voluntary relinquishment or abandonment of a known existing right, or conduct such as warrants an inference of the relinquishment of a known right or privilege." (per S. K. Das, J.) 9. A waiver of a privilege or a right to be effective must be based upon full knowledge of the privilege or right to which the person waiving them is entitled. See Shri A.C. Dutta v. Mst. Bibi Ahmedi Begam, 1954 A.L.J. 622. There is nothing to show that when the assessee filed the return he was aware of his right to object to the validity of the notice on the ground that it permitted him a period of twenty four hours only to furnish the return. The burden lay upon the State to prove all the facts constituting waiver. There is no finding from which it can be inferred that that burden has been discharged. Indeed, it seems that the Revision Board did not apply its mind to this aspect of the question. It concluded from the mere fact of the assessee filing a return that he had waived his objection to the defect in the return. Question No. 3 must, therefore, be answered in the negative. 10. We direct that a copy of this judgment shall be sent to the Revision Board under the seal of the Court and the signature of the Registrar. The assessee shall be entitled to its costs which we assess at Rs. 100. Costs of counsel are assessed at Rs. 100.