JUDGMENT Bhaskar Bhattacharya, J. By this writ application the petitioners have challenged ex parte assessment orders dated November 6, 2001 and January 29, 2002 passed by the Hearing Officer in respect of the annual valuation of the premises in question with effect from 4th quarter of1990-1991 and 4th quarter of 1996 - 1997 respectively. 2. The grievance of the writ petitioners is that although by a letter dated June 1, 1988 the petitioner No.1 asked the Corporation to send subsequent bills at 25, Ballygunge Park instead of the previous mailing address and the Corporation acted upon such instruction by sending subsequent bills at the changed address, but curiously enough, the notice of hearing for the aforesaid two periods were sent under certificate of posting at the previous address, as a result, the petitioners were not aware of the proceedings of annual valuation. The petitioners thus pray for setting aside the ex parte orders impugned herein. 3. Although no affidavit has been filed by the Corporation, records of the cases were produced showing that the petitioner No.1 entered appearance in the hearing of assessment in respect of 4th quarter of 1996-97, filed objection and also prayed for adjournment. It is however admitted position that notices of hearing were issued at the old address. 4. So far assessment order with effect from fourth quarter of 1990-91 is concerned, the petitioner did not enter appearance and at the same time, it is clear that no notice of hearing was even sent to the changed address. Thus, the ex parte assessment order with effect from fourth quarter of 1990-91 was not preceded by a notice inviting objection sent or served at the recorded mailing address. The petitioners claim that they did not receive the notice sent at the previous address and no material has been placed before court falsifying such allegation. The Corporation could not justify its failure to send notice of hearing at the latest mailing address as required under the Kolkata Municipal Corporation Act ("Act"). The aforesaid ex parte order was therefore patently illegal and without jurisdiction. 5. Mr. The Corporation could not justify its failure to send notice of hearing at the latest mailing address as required under the Kolkata Municipal Corporation Act ("Act"). The aforesaid ex parte order was therefore patently illegal and without jurisdiction. 5. Mr. Das Adhikary, the learned counsel appearing on behalf of the Corporation raised a preliminary objection as to th8 maintainability of this writ application on the ground that the order impugned is an appealable one under the aforesaid Act and this Court should not entertain this writ application as the petitioners have not availed of such alternative remedy. 6. I am however not impressed by such submission of Mr. Das Adhikary. The order impugned herein having been passed in breach of a mandatory statutory provision and in violation of the principles of natural justice, I am inclined to entertain this application against ex parte assessment order with effect from fourth quarter of 1990-91 notwithstanding the fact that there is an alternative remedy. 7. I thus quash the aforesaid order and direct the Hearing Officer to start afresh after issuing fresh notice inviting objection as required under the Act. 8. So far the other assessment order with effect from fourth quarter of 199697 is concerned, I however find substance in the contention of Mr. Das Adhikary that this writ application should not be entertained against such order as the petitioner has alternative remedy by way of an appeal before Tribunal. 9. As regards this order, although no notice was issued at the mailing address the petitioner No.1 entered appearance and filed objection against proposed valuation contending that there had been no rise in rent and value of the land since last valuation. In this writ application, the petitioners have suppressed the fact that they had filed written objection against the proposed valuation. In the writ petition they merely alleged that on January 29, 2002 an application for adjournment was filed but the Hearing Officer without disposing of such prayer proceeded ex parte. 10. It appears from Annexure "P-5" of the writ application that on January 8, 2002 an application for adjournment was prayed for 21 days. The copy of the application for adjournment alleged to have been again filed on January 29, 2002 has not been annexed to the application. 10. It appears from Annexure "P-5" of the writ application that on January 8, 2002 an application for adjournment was prayed for 21 days. The copy of the application for adjournment alleged to have been again filed on January 29, 2002 has not been annexed to the application. It further appears from the order dated January 29, 2002 that the authorized representative of the petitioner No.1 was present and the objection was pressed. There is no reference of any prayer for adjournment. 11. Thus, from the conduct of the petitioners it is clear that they waived the notice of hearing. Once a party inspite of non-service of summons enters appearance and files written objection against the claim of the other side, in the same breath, such party after disposal of the proceedings, cannot impugn the order on the ground of irregularity of the service of notice of the proceedings. 12. The learned counsel appearing for the petitioners vehemently contended that service of a notice under section 184 of the Act is mandatory in nature and cannot be waived. In support of such conclusion he relied upon various decisions holding that a notice under section 124 of the Customs Act, 1962 or one under Central Excise Act, 1944 or an ejectment notice under Rent Control Acts cannot be waived. 13. It is now settled law that an ejectment notice being in the nature of condition precedent which has to be complied with before instituting a suit for ejectment and such mandatory provision in the statute having been incorporated as a measure of public policy, cannot be waived. 14. Similar is the position of law in respect of notice under section 124 of the Customs Act which mandates that "no order confiscating any goods or imposing any penalty on any person shall be made unless the owner of the goods or such person is given a notice in writing informing him of the grounds on which it is proposed to confiscate the goods or to impose a penalty" 15. But as pointed out by the Supreme Court in the case of Mangalore Chemicals and Fertilisers Ltd. vs. Deputy Commissioner, Commercial Taxes, ( AIR 1992 SC 152 at page 157), there are conditions and conditions. Some may be substantive, mandatory and based on considerations of policy and some others may merely belong to the area of procedure. But as pointed out by the Supreme Court in the case of Mangalore Chemicals and Fertilisers Ltd. vs. Deputy Commissioner, Commercial Taxes, ( AIR 1992 SC 152 at page 157), there are conditions and conditions. Some may be substantive, mandatory and based on considerations of policy and some others may merely belong to the area of procedure. It will be erroneous, the Apex Court held, to attach equal importance to the non-observance of all conditions irrespective of purposes they were intended to serve. 16. The object of notice under section 184 of the Act is to provide the person liable to pay tax, an opportunity to raise objection. If such a person without notice appears, then prays for adjournment which is granted and also f les written objection against proposed enhancement on merit and ultimately takes part in the proceedings without insisting on service of a notice under section 184, such person cannot subsequently allege non-service of notice under section 184 as a ground while impugning the final order. I have already pointed out that the representative of the petitioner was present on January 29, 2002 when final order was passed. The position, however, would have been different, if the petitioners after entering appearance complained before the Hearing Officer that in the absence of a notice they were unable to raise any objection against the proposed valuation. If such prayer is made, it is the duty of the Hearing Officer to pass direction for service of notice under section 184 and to fix a date after the expiry of the time mentioned in section 184 of the Act. 17. Therefore, I am of the view that the provisions of section 184 of the Act belong to the domain of procedure and can be waived by a party and such waiver can be inferred from his conduct. The petitioners in this case by their conduct have invited the Hearing Officer to adjudicate their objection to the proposed enhancement and thus are estopped from disputing the legality of the final order on the ground of want of a notice under section 184 of the Act. 18. Therefore, the order dated January 29, 2002, passed by the Hearing Officer does not suffer from illegality for want of a valid notice. If the petitioners are dissatisfied with such order on merit, they have an alternative remedy of appeal before Tribunal. 18. Therefore, the order dated January 29, 2002, passed by the Hearing Officer does not suffer from illegality for want of a valid notice. If the petitioners are dissatisfied with such order on merit, they have an alternative remedy of appeal before Tribunal. Therefore, I am not inclined to enter into the merit of the order dated January 29, 2002. 19. I thus set aside the order dated November 6, 2001 passed by the Hearing Officer and direct him to proceed afresh after giving opportunity of hearing to the petitioners. 20. As regards order dated January 29, 2002 I refuse to entertain this application making it clear that I have not entered into merit. Writ application partly allowed.