SUPPLEMENTAL NOTICE OF2023 ANNUAL GENERAL MEETING

Hong Kong Exchanges and Clearing Limited and The Stock Exchange of Hong Kong Limited take no responsibility for the contents of this supplemental notice make no representation as to its accuracy or completeness and expressly disclaim any liability whatsoever for any loss howsoever arising from or in reliance upon the whole or any part of the contents of this supplemental notice.Datang Environment Industry Group Co. Ltd.* (A joint stock company incorporated in the People’s Republic of China with limited liability) (Stock Code: 1272) SUPPLEMENTAL NOTICE OF 2023 ANNUAL GENERAL MEETING Reference is made to the notice (the “Original Notice”) of the 2023 annual general meeting (the “2023 AGM”) of Datang Environment Industry Group Co. Ltd.* (the “Company”) dated 29 May 2024. This supplemental notice (the “Supplemental Notice”) should be read together with the Original Notice.SUPPLEMENTAL NOTICE IS HEREBY GIVEN that the 2023 AGM will be convened at 3:30 p.m. on Friday 28 June 2024 at No. 120 Zizhuyuan Road Haidian District Beijing the PRC as scheduled. Terms used in this supplemental notice shall have the same meanings as those defined in the supplemental circular of the Company dated 13 June 2024 (the “Supplemental Circular”) unless otherwise specified.In addition to the resolutions set out in the Original Notice the following additional resolutions will be considered and if thought fit to be approved at the 2023 AGM: Ordinary Resolution (9) To consider and approve the re-appointment of Moore CPA Limited and Da Hua CPAs (Special General Partnership) as international and domestic auditors of the Company for 2024 respectively with terms of engagement ended upon the conclusion of the 2024 annual general meeting of the Company and the grant of authority to the Board which further grants such authority to the senior management of the Company to determine remunerations of the auditors.Special Resolution (11) To consider and approve the Proposed Domestic Issuance of Corporate Bonds. * For identification purposes only - 1 -Note: The special resolution No. 9 as set out in the Original Notice shall be re-numbered as special resolution No. 10.For details of the above new resolutions please refer to the Supplemental Circular of the Company dated 13 June 2024.This Supplemental Notice should be read in conjunction with the Original Notice. Apart from the amendments set out above all the information contained in the Original Notice shall remain to have full force and effect.By order of the Board Datang Environment Industry Group Co. Ltd.* Zhu Liming Chairman Beijing the PRC 13 June 2024 Notes: (i) Save as the resolutions newly proposed there are no any other changes to the resolution set out in the Original Notice. For details of other resolutions and other related matters to be considered at the 2023 AGM please refer to the notice and circular of the 2023 AGM issued by the Company on 29 May 2024.(ii) As the proxy form published by the Company on the websites of the Stock Exchange(www.hkexnews.hk) and the Company (www.dteg.com.cn) on 29 May 2024 (the “Original ProxyForm”) does not contain the newly added resolutions set out in this supplemental notice a revised proxy form containing the above newly added resolutions (the “Revised 2023 AGM Proxy Form”) has been prepared and is enclosed in this Supplemental Notice.(iii) Important: If a Shareholder of the Company has not yet lodged the Original Proxy Form with the H Share Registrar or the Board office of the Company in the PRC such Shareholder is requested to lodge only the Revised 2023 AGM Proxy Form. A Shareholder who has lodged the Original Proxy Form with the H Share Registrar or the Board office of the Company in the PRC should note that: (1) the duly completed Revised 2023 AGM Proxy Form will be treated as the valid proxy form lodged by such Shareholder; (2) if such Shareholder fails to lodge the Revised 2023 AGM Proxy Form with the H Share Registrar or the Board office of the Company in the PRC the lodged Original Proxy Form if duly completed will remain effective and applicable to the extent permissible. For the additional resolutions not set out in the Original Proxy Form the proxy appointed under the Original Proxy Form shall have the right to vote at his/her discretion if no relevant instruction is received; and (3) any Revised 2023 AGM Proxy Form which is lodged with the H Share Registrar or the Board office of the Company in the PRC after the Deadline (as defined below) shall be invalid. The Original Proxy Form previously lodged by such Shareholder shall not be revoked. The Original Proxy Form if duly completed will be deemed effective and applicable to the extent permissible.- 2 -For the additional resolutions not set out in the Original Proxy Form the proxy appointed under the Original Proxy Form shall have the right to vote at his/her discretion if no relevant instruction is received.(iv) Each Shareholder entitled to attend and vote at the 2023 AGM may by completing the Revised 2023 AGM Proxy Form appoint one or more proxies to attend and vote at the 2023 AGM on its behalf. A proxy need not be a Shareholder. With respect to any Shareholder who has appointed more than one proxy the proxy holders may only vote on a poll.(v) The Revised 2023 AGM Proxy Form shall be signed by the appointer or his attorney duly authorised in writing or in the case of a legal person must be either executed under its common seal or under the hand of its directors or attorney duly authorised.(vi) To be valid the Revised 2023 AGM Proxy Form must be lodged with the H Share Registrar Computershare Hong Kong Investor Services Limited at 17M Floor Hopewell Centre 183 Queen’s Road East Wanchai Hong Kong (for holders of H Shares) or the Company’s Board office in the PRC at No. 120 Zizhuyuan Road Haidian District Beijing the PRC 100097 (for holders of Domestic Shares) not less than 24 hours prior to the holding of the 2023 AGM or any adjourned meetings (the “Deadline”). If the Revised 2023 AGM Proxy Form is signed by another person under a power of attorney or other authorisation documents given by the appointer such power of attorney or other authorisation documents shall be notarised. The notarised power of attorney or other authorisation documents shall together with the Revised 2023 AGM Proxy Form be deposited at the specified place at the time set out in such form. Completion and return of the Revised 2023 AGM Proxy Form will not preclude Shareholders from attending and voting in person at the 2023 AGM or any adjourned meetings should you so wish.As at the date of this Supplemental Notice the executive Director is Mr. Zhu Liming; the non- executive Directors are Mr. Wang Junqi Mr. Shen Zhen Mr. Wu Daqing Mr. Chen Kan and Mr.Song Yunpeng; and the independent non-executive Directors are Mr. Ye Xiang Mr. Mao Zhuanjian and Mr. Gao Jiaxiang.This Supplemental Notice is available on the websites of the Stock Exchange (www.hkexnews.hk) and the Company (www.dteg.com.cn).