UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER PURSUANT TO RULE 13a-16 OR 15d-16 UNDER THE SECURITIES EXCHANGE ACT OF 1934

~~SECURITIES~~For ~~EXCHANGE~~the ~~ACT~~month OFof ~~1934~~May, 2025

For the month of December, 2024

Commission File Number 001-42007

CDT Environmental Technology Investment Holdings Limited

(Translation of registrant’s name into English)

C1, 4th Floor, Building 1, Financial Base, No. 8 Kefa Road ~~Nanshan District, Shenzhen, China 518057 (Address of principal executive office)~~

Nanshan District, Shenzhen, China 518057

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F. Form 20-F ☒ Form 40-F ☐

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1): ☐

Note: Regulation S-T Rule 101(b)(1) only permits the submission in paper of a Form 6-K if submitted solely to provide an attached annual report to security holders.

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7): ☐

Note: Regulation S-T Rule 101(b)(7) only permits the submission in paper of a Form 6-K if submitted to furnish a report or other document that the registrant foreign private issuer must furnish and make public under the laws of the jurisdiction in which the registrant is incorporated, domiciled or legally organized (the registrant’s “home country”), or under the rules of the home country exchange on which the registrant’s securities are traded, as long as the report or other document is not a press release, is not required to be and has not been distributed to the registrant’s security holders, and, if discussing a material event, has already been the subject of a Form 6-K submission or other Commission filing on EDGAR.

1On May 15, 2025, CDT Environmental Technology Investment Holdings Limited issued a press release, a copy of which is attached hereto as Exhibit 99.1and is incorporated herein by reference.

On December 27, 2024, CDT Environmental Technology Investment Holdings Limited issued a press release announcing its unaudited interim financial results for the first half of 2024, a copy of which is attached hereto as Exhibit 99.1 and is incorporated herein by reference.

Exhibit No.	Description of Exhibit
99.1	Press Release dated May 14, 2025

Exhibit No.		Description of Exhibit
99.1		Press Release dated December 27, 2024

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Date: ~~December~~May 2715, ~~2024~~ 2025

CDT ~~ENVIRONMENTAL~~Environmental ~~TECHNOLOGY~~Technology ~~INVESTMENT~~Investment ~~HOLDINGS~~Holdings ~~LIMITED~~Limited By: /s/ Yunwu Li Name: Yunwu Li Title: Chief Executive Officer and Chairman of the Board of Directors

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