UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT UNDER SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 CLEANTECH ACQUISITION CORP. (Exact name of registrant as specified in its charter) Delaware 85-1699753 (State or other jurisdiction of incorporation or organization) (IRS Employer Identification No.) 207 West 25th Street, 9th Floor New York, NY 10001 For the quarterly period ended March 31, 2022 ☐ TRANSITION REPORT PURSUANT TO SECTIO ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2021 or ☐ TRANSITION REPORT UNDER SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from _____________ to ________________ Commission file number: 001-40611 CLEANTECH ACQUISITION CORP. (Exact name of registrant as specified in its charter) | Delaware | 85-1699753 | | - ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT UNDER SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2021 ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from ______________ to ______________ Commission File Number 001-40611 CLEANTECH ACQUISITION CORP. (Exact name of registrant as specified in its charter) (State or othe ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) 207 West 25th Street, 9th Floor New York, NY 10001 ☒ QUARTERLY REPORT UNDER SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2021 ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from ______________ to ______________ Commission File Number 001-40611 CLEANTECH ACQUISITION CORP. (Exact name of registra ...