Exhibit 10.6


 


INDEMNITY AGREEMENT


 


THIS INDEMNITY AGREEMENT (this
“Agreement”) is made as of [_______], 2021, by and between CleanTech Acquisition Corp., a Delaware corporation
(the “Company”), and [_________] (“Indemnitee”).


 


RECITALS


 


WHEREAS, highly competent
persons have become more reluctant to serve publicly held corporations as directors, officers or in other capacities unless they are provided
with adequate protection through insurance or adequate indemnification against inordinate risks of claims and actions against them arising
out of their service to and activities on behalf of such corporations.


 


WHEREAS, the Board
of Directors of the Company (the “Board”) has determined that, in order to attract and retain qualified individuals,
the Company will attempt to maintain on an ongoing basis, at its sole expense, liability insurance to protect persons serving the Company
and its Subsidiaries from certain liabilities. Although the furnishing of such insurance has been a customary and widespread practice
among United States-based corporations and other business enterprises, the Company believes that, given current market conditions and
trends, such insurance may be available to it in the future only at higher premiums and with more exclusions. At the same time, directors,
officers and other persons in service to corporations or business enterprises are being increasingly subjected to expensive and time-consuming
litigation relating to, among other things, matters that traditionally would have been brought only against the Company or business enterprise
itself. The Amended and Restated Certificate of Incorporation (the “Charter”) and the Bylaws (the “Bylaws”)
of the Company require indemnification of the officers and directors of the Company. Indemnitee may also be entitled to indemnification
pursuant to applicable provisions of the Delaware General Corporation Law (the “DGCL”). The Bylaws and the DGCL
expressly provide that the indemnification provisions set forth therein are not exclusive, and thereby contemplate that contracts may
be entered into between the Company and members of the board of directors, officers and other persons with respect to indemnification,
hold harmless, exoneration, advancement and reimbursement rights.


 


WHEREAS, the uncertainties
relating to such insurance and to indemnification have increased the difficulty of attracting and retaining such persons.


 


WHEREAS, the Board
has determined that the increased difficulty in attracting and retaining such persons is detrimental to the best interests of the Company’s
stockholders and that the Company should act to assure such persons that there will be increased certainty of such protection in the future.


 


WHEREAS, it is reasonable,
prudent and necessary for the Company contractually to obligate itself to indemnify, hold harmless, exonerate and to advance expenses
on behalf of, such persons to the fullest extent permitted by applicable law so that they will serve or continue to serve the Company
free from undue concern that they will not be so protected against liabilities.


 


WHEREAS, this Agreement
is a supplement to and in furtherance of the Charter and Bylaws of the Company and any resolutions adopted pursuant thereto, and shall
not be deemed a substitute therefor, nor to diminish or abrogate any rights of Indemnitee thereunder.


 


WHEREAS, Indemnitee
may not be willing to serve as an officer or director without adequate protection, and the Company desires Indemnitee to serve in such
capacity. Indemnitee is willing to serve, continue to serve and to take on additional service for or on behalf of the Company on the condition
that he or she be so indemnified.


 






     


     


    

 


NOW, THEREFORE, in
consideration of the premises and the covenants contained herein, the Company and Indemnitee do hereby covenant and agree as follows:


 


TERMS AND CONDITIONS


 





		1.	SERVICES TO THE COMPANY. Indemnitee will serve or continue to serve as an officer, director, advisor, key employee or in any other capacity of the Company, as applicable, for so long as Indemnitee is duly elected, appointed or retained or until Indemnitee tenders his or her resignation, or is removed or dies. The foregoing notwithstanding, this Agreement shall continue in full force and effect after Indemnitee has ceased to serve as an officer, director, advisor, key employee or in any other capacity of the Company, as provided in Section 17. This Agreement, however, shall not impose any obligation on Indemnitee or the Company to continue Indemnitee’s service to the Company beyond any period otherwise required by law or by other agreements or commitments of the parties, if any





 


		2.	DEFINITIONS. As used in this Agreement:


 


(a) References to “agent”
shall mean any person who is or was a director, officer or employee of the Company or a Subsidiary of the Company or other person authorized
by the Company to act for the Company, to include such person serving in such capacity as a director, officer, employee, fiduciary or
other official of another corporation, partnership, limited liability company, joint venture, trust or other enterprise at the request
of, for the convenience of, or to represent the interests of the Company or a Subsidiary of the Company.


 


(b) The terms “Beneficial
Owner” and “Beneficial Ownership” shall have the meanings set forth in Rule 13d-3 promulgated
under the Exchange Act as in effect on the date hereof.


 


(c) A “Change in Control”
shall be deemed to occur upon the earliest to occur after the date of this Agreement of any of the following events:


 


(i) Acquisition of Stock by Third Party.
Other than CleanTech Sponsor I LLC or CleanTech Investments, LLC (the “Co-Sponsors”) or an affiliate thereof,
any Person is or becomes the Beneficial Owner, directly or indirectly, of securities of the Company representing fifteen percent (15%)
or more of the combined voting power of the Company’s then outstanding securities entitled to vote generally in the election of
directors, unless (1) the change in the relative Beneficial Ownership of the Company’s securities by any Person results solely from
a reduction in the aggregate number of outstanding shares of securities entitled to vote generally in the election of directors, or (2)
such acquisition was approved in advance by the Continuing Directors and such acquisition would not constitute a Change in Control under
part (iii) of this definition;


 






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(ii) Change in Board of Directors.
Individuals who, as of the date hereof, constitute the Board, and any new director whose election by the Board or nomination for election
by the Company’s stockholders was approved by a vote of at least two thirds of the directors then still in office who were directors
on the date hereof or whose election for nomination for election was previously so approved (collectively, the “Continuing
Directors”), cease for any reason to constitute at least a majority of the members of the Board;


 


(iii) Corporate Transactions. The
effective date of a merger, share exchange, asset acquisition, stock purchase, recapitalization or other similar business combination
involving the Company and one or more businesses or entities (a “Business Combination”), in each case, unless,
following such Business Combination: (1) all or substantially all of the individuals and entities who were the Beneficial Owners of securities
entitled to vote generally in the election of directors immediately prior to such Business Combination beneficially own, directly or indirectly,
more than fifty-one percent (51%) of the combined voting power of the then outstanding securities of the Company entitled to vote generally
in the election of directors resulting from such Business Combination (including, without limitation, a corporation which as a result
of such transaction owns the Company or all or substantially all of the Company’s assets either directly or through one or more
Subsidiaries) in substantially the same proportions as their ownership immediately prior to such Business Combination, of the securities
entitled to vote generally in the election of directors; (2) other than any Co-Sponsor or an affiliate thereof, no Person (excluding any
corporation resulting from such Business Combination) is the Beneficial Owner, directly or indirectly, of fifteen percent (15%) or more
of the combined voting power of the then outstanding securities entitled to vote generally in the election of directors of the surviving
corporation except to the extent that such ownership existed prior to the Business Combination; and (3) at least a majority of the Board
of Directors of the corporation resulting from such Business Combination were Continuing Directors at the time of the execution of the
initial agreement, or of the action of the Board of Directors, providing for such Business Combination;


 


(iv) Liquidation. The approval
by the stockholders of the Company of a complete liquidation of the Company or an agreement or series of agreements for the sale or disposition
by the Company of all or substantially all of the Company’s assets, other than factoring the Company’s current receivables
or escrows due (or, if such approval is not required, the decision by the Board to proceed with such a liquidation, sale, or disposition
in one transaction or a series of related transactions); or


 


(v) Other Events. There occurs
any other event of a nature that would be required to be reported in response to Item 6(e) of Schedule 14A of Regulation 14A (or a response
to any similar item on any similar schedule or form) promulgated under the Exchange Act, whether or not the Company is then subject to
such reporting requirement.


 






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(d) “Corporate Status”
describes the status of a person who is or was a director, officer, trustee, general partner, manager, managing member, fiduciary, employee
or agent of the Company or of any other Enterprise which such person is or was serving at the request of the Company.


 


(e) “Delaware Court”
shall mean the Court of Chancery of the State of Delaware.


 


(f) “Disinterested Director”
shall mean a director of the Company who is not and was not a party to the Proceeding in respect of which indemnification is sought by
Indemnitee.


 


(g) “Enterprise”
shall mean the Company and any other corporation, constituent corporation (including any constituent of a constituent) absorbed in a consolidation
or merger to which the Company (or any of its wholly owned Subsidiaries) is a party, limited liability company, partnership, joint venture,
trust, employee benefit plan or other enterprise of which Indemnitee is or was serving at the request of the Company as a director, officer,
trustee, general partner, managing member, fiduciary, employee or agent.


 


(h) “Exchange Act”
shall mean the Securities Exchange Act of 1934, as amended.


 


(i) “Expenses”
shall include all direct and indirect costs, fees and expenses of any type or nature whatsoever, including, without limitation, all reasonable
attorneys’ fees and costs, retainers, court costs, transcript costs, fees of experts, witness fees, travel expenses, fees of private
investigators and professional advisors, duplicating costs, printing and binding costs, telephone charges, postage, delivery service fees,
fax transmission charges, secretarial services and all other disbursements, obligations or expenses in connection with prosecuting, defending,
preparing to prosecute or defend, investigating, being or preparing to be a witness in, settlement or appeal of, or otherwise participating
in, a Proceeding, including reasonable compensation for time spent by the Indemnitee for which he or she is not otherwise compensated
by the Company or any third party. Expenses also shall include Expenses incurred in connection with any appeal resulting from any Proceeding,
including without limitation the principal, premium, security for, and other costs relating to any cost bond, supersedeas bond, or other
appeal bond or its equivalent. Expenses, however, shall not include amounts paid in settlement by Indemnitee or the amount of judgments
or fines against Indemnitee.


 


(j) References to “fines”
shall include any excise tax assessed on Indemnitee with respect to any employee benefit plan; references to “serving at the request
of the Company” shall include any service as a director, officer, employee, agent or fiduciary of the Company which imposes duties
on, or involves services by, such director, officer, employee, agent or fiduciary with respect to an employee benefit plan, its participants
or beneficiaries; and if Indemnitee acted in good faith and in a manner Indemnitee reasonably believed to be in the best interests of
the participants and beneficiaries of an employee benefit plan, Indemnitee shall be deemed to have acted in a manner “not opposed
to the best interests of the Company” as referred to in this Agreement.


 






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(k) “Independent Counsel”
shall mean a law firm or a member of a law firm with significant experience in matters of corporate law and that neither presently is,
nor in the past five years has been, retained to represent: (i) the Company or Indemnitee in any matter material to either such party
(other than with respect to matters concerning the Indemnitee under this Agreement, or of other indemnitees under similar indemnification
agreements); or (ii) any other party to the Proceeding giving rise to a claim for indemnification hereunder. Notwithstanding the foregoing,
the term “Independent Counsel” shall not include any person who, under the applicable standards of professional conduct then
prevailing, would have a conflict of interest in representing either the Company or Indemnitee in an action to determine Indemnitee’s
rights under this Agreement.


 


(l) The term “Person”
shall have the meaning as set forth in Sections 13(d) and 14(d) of the Exchange Act as in effect on the date hereof; provided, however,
that “Person” shall exclude: (i) the Company; (ii) any Subsidiaries of the Company; (iii) any employment benefit plan of the
Company or of a Subsidiary of the Company or of any corporation owned, directly or indirectly, by the stockholders of the Company in substantially
the same proportions as their ownership of stock of the Company; and (iv) any trustee or other fiduciary holding securities under an employee
benefit plan of the Company or of a Subsidiary of the Company or of a corporation owned directly or indirectly by the stockholders of
the Company in substantially the same proportions as their ownership of stock of the Company.


 


(m) The term “Proceeding”
shall include any threatened, pending or completed action, suit, arbitration, mediation, alternate dispute resolution mechanism, investigation,
inquiry, administrative hearing or any other actual, threatened or completed proceeding, whether brought in the right of the Company or
otherwise and whether of a civil (including intentional or unintentional tort claims), criminal, administrative or investigative or related
nature, in which Indemnitee was, is, will or might be involved as a party or a participant (as a witness or otherwise), by reason of his
or her Corporate Status or by reason of any action (or failure to act) taken by him or of any action (or failure to act) on his part while
acting as a director or officer of the Company, in each case whether or not serving in such capacity at the time any liability or expense
is incurred for which indemnification, reimbursement, or advancement of expenses can be provided under this Agreement.


 


(n) The term “Subsidiary,”
with respect to any Person, shall mean any corporation, limited liability company, partnership, joint venture, trust or other entity of
which a majority of the voting power of the voting equity securities or equity interest is owned, directly or indirectly, by that Person.


 


		3.	INDEMNITY IN THIRD-PARTY PROCEEDINGS. To the fullest extent permitted by applicable law, the Company shall indemnify, hold harmless and exonerate Indemnitee in accordance with the provisions of this Section 3 if Indemnitee was, is, or is threatened to be made, a party to or a participant (as a witness, deponent or otherwise) in any Proceeding, other than a Proceeding by or in the right of the Company to procure a judgment in its favor. Pursuant to this Section 3, Indemnitee shall be indemnified, held harmless and exonerated against all Expenses, judgments, liabilities, fines, penalties and amounts paid in settlement (including all interest, assessments and other charges paid or payable in connection with or in respect of such Expenses, judgments, fines, penalties and amounts paid in settlement) actually and reasonably incurred by Indemnitee or on his or her behalf in connection with such Proceeding or any claim, issue or matter therein, if Indemnitee acted in good faith and in a manner he or she reasonably believed to be in or not opposed to the best interests of the Company and, in the case of a criminal Proceeding, had no reasonable cause to believe that his or her conduct was unlawful.

                                                     




 






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		4.	INDEMNITY IN PROCEEDINGS BY OR IN THE RIGHT OF THE COMPANY. To the fullest extent permitted by applicable law, the Company shall indemnify, hold harmless and exonerate Indemnitee in accordance with the provisions of this Section 4 if Indemnitee was, is, or is threatened to be made, a party to or a participant (as a witness, deponent or otherwise) in any Proceeding by or in the right of the Company to procure a judgment in its favor. Pursuant to this Section 4, Indemnitee shall be indemnified against all Expenses actually and reasonably incurred by him or her or on his or her behalf in connection with such Proceeding or any claim, issue or matter therein, if Indemnitee acted in good faith and in a manner he or she reasonably believed to be in or not opposed to the best interests of the Company. No indemnification, hold harmless or exoneration for Expenses shall be made under this Section 4 in respect of any claim, issue or matter as to which Indemnitee shall have been finally adjudged by a court to be liable to the Company, unless and only to the extent that any court in which the Proceeding was brought or the Delaware Court shall determine upon application that, despite the adjudication of liability but in view of all of the circumstances of the case, Indemnitee is fairly and reasonably entitled to indemnification, to be held harmless or to exoneration.

                                                      

		5.	INDEMNIFICATION FOR EXPENSES OF A PARTY WHO IS WHOLLY OR PARTLY SUCCESSFUL. Notwithstanding any other provisions of this Agreement except for Section 27, to the extent that Indemnitee was or is a party to or a participant (as a witness, deponent or otherwise) in and is successful, on the merits or otherwise, in any Proceeding or in defense of any claim, issue or matter therein, in whole or in part, the Company shall, to the fullest extent permitted by applicable law, indemnify, hold harmless and exonerate Indemnitee against all Expenses actually and reasonably incurred by him or her in connection therewith. If Indemnitee is not wholly successful in such Proceeding but is successful, on the merits or otherwise, as to one or more but less than all claims, issues or matters in such Proceeding, the Company shall, to the fullest extent permitted by applicable law, indemnify, hold harmless and exonerate Indemnitee against all Expenses actually and reasonably incurred by him or her or on his or her behalf in connection with each successfully resolved claim, issue or matter. If the Indemnitee is not wholly successful in such Proceeding, the Company also shall, to the fullest extent permitted by applicable law, indemnify, hold harmless and exonerate Indemnitee against all Expenses actually and reasonably incurred in connection with a claim, issue or matter related to any claim, issue, or matter on which the Indemnitee was successful. For purposes of this Section and without limitation, the termination of any claim, issue or matter in such a Proceeding by dismissal, with or without prejudice, shall be deemed to be a successful result as to such claim, issue or matter.

                                                      

		6.	INDEMNIFICATION FOR EXPENSES OF A WITNESS. Notwithstanding any other provision of this Agreement except for Section 27, to the extent that Indemnitee is a participant (as a witness or otherwise) in any Proceeding to which Indemnitee is not a party, he or she shall, to the fullest extent permitted by applicable law, be indemnified, held harmless and exonerated against all Expenses actually and reasonably incurred by him or her or on his or her behalf in connection therewith.

                                                     




 






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		7.	ADDITIONAL INDEMNIFICATION, HOLD HARMLESS AND EXONERATION RIGHTS.


 


Notwithstanding any limitation in Sections
3, 4, or 5, the Company shall, to the fullest extent permitted by applicable law, indemnify, hold harmless and exonerate Indemnitee if
Indemnitee is a party to or threatened to be made a party to any Proceeding (including a Proceeding by or in the right of the Company
to procure a judgment in its favor) against all Expenses, judgments, fines, penalties and amounts paid in settlement (including all interest,
assessments and other charges paid or payable in connection with or in respect of such Expenses, judgments, fines, penalties and amounts
paid in settlement) actually and reasonably incurred by Indemnitee in connection with the Proceeding. No indemnification, hold harmless
or exoneration rights shall be available under this Section 7 on account of Indemnitee’s conduct which constitutes a breach of Indemnitee’s
duty of loyalty to the Company or its stockholders, including an act or omission of Indemnitee not in good faith, or which involves intentional
misconduct or a knowing violation of the law.


 


	8.	CONTRIBUTION IN THE EVENT OF JOINT LIABILITY.


 


		(a)	To the fullest extent permissible under applicable law, if the indemnification, hold harmless and/or exoneration rights provided for
in this Agreement are unavailable to Indemnitee in whole or in part for any reason whatsoever, the Company, in lieu of indemnifying, holding
harmless or exonerating Indemnitee, shall pay, in the first instance, the entire amount incurred by Indemnitee, whether for judgments,
liabilities, fines, penalties, amounts paid or to be paid in settlement and/or for Expenses, in connection with any Proceeding without
requiring Indemnitee to contribute to such payment, and the Company hereby waives and relinquishes any right of contribution it may have
at any time against Indemnitee.



 


		(b)	The Company shall not enter into any settlement of any Proceeding in which the Company is jointly liable with Indemnitee (or would
be if joined in such Proceeding) unless such settlement provides for a full and final release of all claims asserted against Indemnitee.



 


		(c)	The Company hereby agrees to fully indemnify, hold harmless and exonerate Indemnitee from any claims for contribution which may be
brought by officers, directors or employees of the Company, other than Indemnitee, who may be jointly liable with Indemnitee.



 


		9.	EXCLUSIONS. Notwithstanding any provision in this Agreement except for Section 27, the Company shall not be obligated under this Agreement to make any indemnification, hold harmless or exoneration payment in connection with any claim made against Indemnitee:


 


(a) for which payment has actually been
received by or on behalf of Indemnitee under any insurance policy or other indemnity provision, except with respect to any excess beyond
the amount actually received under any insurance policy, contract, agreement, other indemnity provision or otherwise;


 






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(b) for an accounting of profits made
from the purchase and sale (or sale and purchase) by Indemnitee of securities of the Company within the meaning of Section 16(b) of the
Exchange Act or similar provisions of state statutory law or common law; or


 


(c) except as otherwise provided in
Sections 14(e)-(f) hereof, prior to a Change in Control, in connection with any Proceeding (or any part of any Proceeding) initiated by
Indemnitee, including any Proceeding (or any part of any Proceeding) initiated by Indemnitee against the Company or its directors, officers,
employees or other indemnitees, unless (i) the Board authorized the Proceeding (or any part of any Proceeding) prior to its initiation
or (ii) the Company provides the indemnification, hold harmless or exoneration payment, in its sole discretion, pursuant to the powers
vested in the Company under applicable law.


 


		10.	ADVANCES OF EXPENSES; DEFENSE OF CLAIM.


 


(a) Notwithstanding any provision of
this Agreement to the contrary except for Section 27, and to the fullest extent not prohibited by applicable law, the Company shall pay
the Expenses incurred by Indemnitee (or reasonably expected by Indemnitee to be incurred by Indemnitee within three months) in connection
with any Proceeding within ten (10) days after the receipt by the Company of a statement or statements requesting such advances from time
to time, prior to the final disposition of any Proceeding. Advances shall be unsecured and interest free. Advances shall be made without
regard to Indemnitee’s ability to repay the Expenses and without regard to Indemnitee’s ultimate entitlement to be indemnified,
held harmless or exonerated under the other provisions of this Agreement. Advances shall include any and all reasonable Expenses incurred
pursuing a Proceeding to enforce this right of advancement, including Expenses incurred preparing and forwarding statements to the Company
to support the advances claimed. To the fullest extent required by applicable law, such payments of Expenses in advance of the final disposition
of the Proceeding shall be made only upon the Company’s receipt of an undertaking, by or on behalf of the Indemnitee, to repay the
advance to the extent that it is ultimately determined that Indemnitee is not entitled to be indemnified by the Company under the provisions
of this Agreement, the Charter, the Bylaws of the Company, applicable law or otherwise. This Section 10(a) shall not apply to any claim
made by Indemnitee for which an indemnification, hold harmless or exoneration payment is excluded pursuant to Section 9.


 


(b) The Company will be entitled to
participate in the Proceeding at its own expense.


 


(c) The Company shall not settle any
action, claim or Proceeding (in whole or in part) which would impose any Expense, judgment, fine, penalty or limitation that is not entitled
to be indemnified under this Agreement on the Indemnitee without the Indemnitee’s prior written consent.





 






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	11.	PROCEDURE FOR NOTIFICATION AND APPLICATION FOR INDEMNIFICATION.


 


(a) Indemnitee agrees to promptly notify
the Company in writing upon being served with any summons, citation, subpoena, complaint, indictment, information or other document relating
to any Proceeding or matter which may be subject to indemnification, hold harmless or exoneration rights, or advancement of Expenses covered
hereunder. The failure of Indemnitee to so notify the Company shall not relieve the Company of any obligation which it may have to the
Indemnitee under this Agreement, or otherwise.


 


(b) Indemnitee may deliver to the Company
a written application to indemnify, hold harmless or exonerate Indemnitee in accordance with this Agreement. Such application(s) may be
delivered from time to time and at such time(s) as Indemnitee deems appropriate in his or her sole discretion. Following such a written
application for indemnification by Indemnitee, the Indemnitee’s entitlement to indemnification shall be determined according to
Section 12(a) of this Agreement.


 


		12.	PROCEDURE UPON APPLICATION FOR INDEMNIFICATION.


 


(a) A determination, if required by
applicable law, with respect to Indemnitee’s entitlement to indemnification shall be made in the specific case by one of the following
methods, which shall be at the election of Indemnitee: (i) by a majority vote of the Disinterested Directors, even though less than a
quorum of the Board, (ii) by a committee of such directors designated by majority vote of such directors, or (iii) by Independent Counsel
in a written opinion to the Board, a copy of which shall be delivered to Indemnitee. The Company will promptly advise Indemnitee in writing
with respect to any determination that Indemnitee is or is not entitled to indemnification, including a description of any reason or basis
for which indemnification has been denied. If it is so determined that Indemnitee is entitled to indemnification, payment to Indemnitee
shall be made within ten (10) days after such determination. Indemnitee shall reasonably cooperate with the person, persons or entity
making such determination with respect to Indemnitee’s entitlement to indemnification, including providing to such person, persons
or entity upon reasonable advance request any documentation or information which is not privileged or otherwise protected from disclosure
and which is reasonably available to Indemnitee and reasonably necessary to such determination. Any costs or Expenses (including reasonable
attorneys’ fees and disbursements) incurred by Indemnitee in so cooperating with the person, persons or entity making such determination
shall be borne by the Company (irrespective of the determination as to Indemnitee’s entitlement to indemnification) and the Company
hereby agrees to indemnify and to hold Indemnitee harmless therefrom.


 


(b) In the event the determination of
entitlement to indemnification is to be made by Independent Counsel pursuant to Section 12(a) hereof, the Independent Counsel shall be
selected as provided in this Section 12(b). The Independent Counsel shall be selected by Indemnitee (unless Indemnitee shall request that
such selection be made by the Board), and Indemnitee shall give written notice to the Company advising it of the identity of the Independent
Counsel so selected and certifying that the Independent Counsel so selected meets the requirements set forth in Section 2(k) hereof. If
the Independent Counsel is selected by the Board, the Company shall give written notice to Indemnitee advising him of the identity of
the Independent Counsel so selected and certifying that the Independent Counsel so selected meets the requirements set forth in Section
2(k) hereof. In either event, Indemnitee or the Company, as the case may be, may, within ten (10) days after such written notice of selection
shall have been received, deliver to the Company or to Indemnitee, as the case may be, a written objection to such selection; provided,
however, that such objection may be asserted only on the ground that the Independent Counsel so selected does not meet the requirements
so selected meets the requirements set forth in Section 2(k) hereof, and the objection shall set forth with particularity the factual
basis of such assertion. Absent a proper and timely objection, the person so selected shall act as Independent Counsel. If such written
objection is so made and substantiated, the Independent Counsel so selected may not serve as Independent Counsel unless and until such
objection is withdrawn or a court of competent jurisdiction has determined that such objection is without merit. If, within twenty (20)
days after submission by Indemnitee of a written request for indemnification pursuant to Section 11(b) hereof, no Independent Counsel
shall have been selected and not objected to, either the Company or Indemnitee may petition the Delaware Court for resolution of any objection
which shall have been made by the Company or Indemnitee to the other’s selection of Independent Counsel and/or for the appointment
as Independent Counsel of a person selected by the Delaware Court, and the person with respect to whom all objections are so resolved
or the person so appointed shall act as Independent Counsel under Section 12(a) hereof. Upon the due commencement of any judicial proceeding
or arbitration pursuant to Section 14(a) of this Agreement, Independent Counsel shall be discharged and relieved of any further responsibility
in such capacity (subject to the applicable standards of professional conduct then prevailing).


 


(c) The Company agrees to pay the reasonable
fees and expenses of Independent Counsel and to fully indemnify and hold harmless such Independent Counsel against any and all Expenses,
claims, liabilities and damages arising out of or relating to this Agreement or its engagement pursuant hereto.


 






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		13.	PRESUMPTIONS AND EFFECT OF CERTAIN PROCEEDINGS.


 


(a) In making a determination with respect
to entitlement to indemnification hereunder, the person, persons or entity making such determination shall presume that Indemnitee is
entitled to indemnification under this Agreement if Indemnitee has submitted a request for indemnification in accordance with Section
11(b) of this Agreement, and the Company shall have the burden of proof to overcome that presumption in connection with the making by
any person, persons or entity of any determination contrary to that presumption. Neither the failure of the Company (including by its
directors or Independent Counsel) to have made a determination prior to the commencement of any action pursuant to this Agreement that
indemnification is proper in the circumstances because Indemnitee has met the applicable standard of conduct, nor an actual determination
by the Company (including by its directors or Independent Counsel) that Indemnitee has not met such applicable standard of conduct, shall
be a defense to the action or create a presumption that Indemnitee has not met the applicable standard of conduct.


 


(b) If the person, persons or entity
empowered or selected under Section 12 of this Agreement to determine whether Indemnitee is entitled to indemnification shall not have
made a determination within thirty (30) days after receipt by the Company of the request therefor, the requisite determination of entitlement
to indemnification shall be deemed to have been made and Indemnitee shall be entitled to such indemnification, absent (i) a misstatement
by Indemnitee of a material fact, or an omission of a material fact necessary to make Indemnitee’s statement not materially misleading,
in connection with the request for indemnification, or (ii) a final judicial determination that any or all such indemnification is expressly
prohibited under applicable law; provided, however, that such thirty (30) day period may be extended for a reasonable time, not to exceed
an additional fifteen (15) days, if the person, persons or entity making the determination with respect to entitlement to indemnification
in good faith require(s) such additional time for the obtaining or evaluating of documentation and/or information relating thereto.


 


(c) The termination of any Proceeding
or of any claim, issue or matter therein, by judgment, order, settlement or conviction, or upon a plea of nolo contendere or its equivalent,
shall not (except as otherwise expressly provided in this Agreement) of itself, favor or undermine the determination of, the right of
Indemnitee to indemnification or create a presumption that Indemnitee did or did not act in good faith and in a manner which he or she
reasonably believed to be in or not opposed to the best interests of the Company or, with respect to any criminal Proceeding, that Indemnitee
had reasonable cause to believe that his or her conduct was unlawful.


 


(d) For purposes of any determination
of good faith, Indemnitee shall be deemed to have acted in good faith if Indemnitee’s action is based on the records or books of
account of the Enterprise, including financial statements, or on information supplied to Indemnitee by the directors, officers or managers
of the Enterprise in the course of their duties, or on the advice of legal counsel for the Enterprise, its Board, any committee of the
Board or any director, officer, trustee, general partner, manager or managing member, or on information or records given or reports made
to the Enterprise, its Board, any committee of the Board or any director, officer, trustee, general partner, manager or managing member,
by an independent certified public accountant or by an appraiser or other expert selected by the Enterprise, its Board, any committee
of the Board or any director, officer, trustee, general partner, manager or managing member. The provisions of this Section 13(d) shall
not be deemed to be exclusive or to limit in any way the other circumstances in which the Indemnitee may be deemed or found to have or
have not met the applicable standard of conduct set forth in this Agreement.


 


(e) The knowledge and/or actions, or
failure to act, of any other director, officer, trustee, partner, managing member, fiduciary, agent or employee of the Enterprise shall
not be imputed to Indemnitee for purposes of determining the right to indemnification under this Agreement.


 




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		14.	REMEDIES OF INDEMNITEE.


 


(a) In the event that (i) a determination
is made pursuant to Section 12 of this Agreement that Indemnitee is not entitled to indemnification under this Agreement, (ii) advancement
of Expenses, to the fullest extent permitted by applicable law, is not timely made pursuant to Section 10 of this Agreement, (iii) no
determination of entitlement to indemnification shall have been made pursuant to Section 12(a) of this Agreement within the timeline set
forth in this Agreement, (iv) payment of indemnification is not made pursuant to Section 5, 6, 7 or the last sentence of Section 12(a)
of this Agreement within the timeline set forth in this Agreement, (v) a contribution payment is not made in a timely manner pursuant
to Section 8 of this Agreement, (vi) payment of indemnification pursuant to Section 3 or 4 of this Agreement is not made within the timeline
set forth in this Agreement, or (vii) payment to Indemnitee pursuant to any hold harmless or exoneration rights under this Agreement or
otherwise is not made within the timeline set forth in this Agreement, Indemnitee shall be entitled to an adjudication by the Delaware
Court to such indemnification, hold harmless, exoneration, contribution or advancement rights. Alternatively, Indemnitee, at his or her
option, may seek an award in arbitration to be conducted by a single arbitrator pursuant to the Commercial Arbitration Rules of the American
Arbitration Association. Except as set forth herein, the provisions of Delaware law (without regard to its conflict of laws rules) shall
apply to any such arbitration. The Company shall not oppose Indemnitee’s right to seek any such adjudication or award in arbitration.


 


(b) In the event that a determination
shall have been made pursuant to Section 12(a) of this Agreement that Indemnitee is not entitled to indemnification, any judicial proceeding
or arbitration commenced pursuant to this Section 14 shall be conducted in all respects as a de novo trial, or arbitration, on the merits
and Indemnitee shall not be prejudiced by reason of that adverse determination. In any judicial proceeding or arbitration commenced pursuant
to this Section 14, Indemnitee shall be presumed to be entitled to be indemnified, held harmless, exonerated to receive advances of Expenses
under this Agreement and the Company shall have the burden of proving Indemnitee is not entitled to be indemnified, held harmless, exonerated
and to receive advances of Expenses, as the case may be, and the Company may not refer to or introduce into evidence any determination
pursuant to Section 12(a) of this Agreement adverse to Indemnitee for any purpose. If Indemnitee commences a judicial proceeding or arbitration
pursuant to this Section 14, Indemnitee shall not be required to reimburse the Company for any advances pursuant to Section 10 until a
final determination is made with respect to Indemnitee’s entitlement to indemnification (as to which all rights of appeal have been
exhausted or lapsed).


 


(c) If a determination shall have been
made pursuant to Section 12(a) of this Agreement that Indemnitee is entitled to indemnification, the Company shall be bound by such determination
in any judicial proceeding or arbitration commenced pursuant to this Section 14, absent (i) a misstatement by Indemnitee of a material
fact, or an omission of a material fact necessary to make Indemnitee’s statement not materially misleading, in connection with the
request for indemnification, or (ii) a prohibition of such indemnification under applicable law.


 






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(d) The Company shall be precluded from
asserting in any judicial proceeding or arbitration commenced pursuant to this Section 14 that the procedures and presumptions of this
Agreement are not valid, binding and enforceable and shall stipulate in any such court or before any such arbitrator that the Company
is bound by all the provisions of this Agreement.


 


(e) The Company shall indemnify and
hold harmless Indemnitee to the fullest extent permitted by law against all Expenses and, if requested by Indemnitee, shall (within ten
(10) days after the Company’s receipt of such written request) pay to Indemnitee, to the fullest extent permitted by applicable
law, such Expenses which are incurred by Indemnitee in connection with any judicial proceeding or arbitration brought by Indemnitee (i)
to enforce his or her rights under, or to recover damages for breach of, this Agreement or any other indemnification, hold harmless, exoneration,
advancement or contribution agreement or provision of the Charter or the Bylaws now or hereafter in effect; or (ii) for recovery or advances
under any insurance policy maintained by any person for the benefit of Indemnitee, regardless of the outcome and whether Indemnitee ultimately
is determined to be entitled to such indemnification, hold harmless or exoneration right, advancement, contribution or insurance recovery,
as the case may be (unless such judicial proceeding or arbitration was not brought by Indemnitee in good faith).


 


(f) Interest shall be paid by the Company
to Indemnitee at the legal rate under Delaware law for amounts which the Company indemnifies, holds harmless or exonerates, contributes,
reimburses, advances, or is obliged to indemnify, hold harmless, exonerate, contribute, reimburse or advance for the period commencing
with the date on which the Indemnitee requests such indemnification, to be held harmless, exonerated, contribution, reimbursement or advancement
of any Expenses and ending with the date on which such payment is made to Indemnitee by the Company.


 


	15.	SECURITY. Notwithstanding anything herein to the contrary, to the extent requested by the Indemnitee and approved by the Board, the Company may at any time and from time to time provide security to the Indemnitee for the Company’s obligations hereunder through an irrevocable bank line of credit, funded trust or other collateral. Any such security, once provided to the Indemnitee, may not be revoked or released without the prior written consent of the Indemnitee.





 


	16.	NON-EXCLUSIVITY; SURVIVAL OF RIGHTS; INSURANCE; SUBROGATION; PRIORITY OF OBLIGATIONS.


 


(a) The rights of Indemnitee as provided
by this Agreement shall not be deemed exclusive of any other rights to which Indemnitee may at any time be entitled under applicable law,
the Charter, the Bylaws, any agreement, a vote of stockholders or a resolution of directors, or otherwise. No amendment, alteration or
repeal of this Agreement or of any provision hereof shall limit or restrict any right of Indemnitee under this Agreement in respect of
any Proceeding (regardless of when such Proceeding is first threatened, commenced or completed) or claim, issue or matter therein arising
out of, or related to, any action taken or omitted by such Indemnitee in his Corporate Status prior to such amendment, alteration or repeal.
To the extent that a change in applicable law, whether by statute or judicial decision, permits greater indemnification, hold harmless
or exoneration rights or advancement of Expenses than would be afforded currently under the Charter, the Bylaws or this Agreement, then
this Agreement (without any further action by the parties hereto) shall automatically be deemed to be amended to require that the Company
indemnifies the Indemnitee to the fullest extent permitted by law. No right or remedy herein conferred is intended to be exclusive of
any other right or remedy, and every other right and remedy shall be cumulative and in addition to every other right and remedy given
hereunder or now or hereafter existing at law or in equity or otherwise,. The assertion or employment of any right or remedy hereunder,
or otherwise, shall not prevent the concurrent assertion or employment of any other right or remedy.


 






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(b) The DGCL and the Bylaws permit the
Company to purchase and maintain insurance or furnish similar protection or make other arrangements including, but not limited to, providing
a trust fund, letter of credit, or surety bond (“Indemnification Arrangements”) on behalf of Indemnitee against
any liability asserted against him or her or incurred by or on behalf of him or her or in such capacity as a director, officer, employee
or agent of the Company, or arising out of his or her status as such, whether or not the Company would have the power to indemnify him
or her against such liability under the provisions of this Agreement or under the DGCL, as it may then be in effect. The purchase, establishment,
and maintenance of any such Indemnification Arrangement shall not in any way limit or affect the rights and obligations of the Company
or of the Indemnitee under this Agreement except as expressly provided herein, and the execution and delivery of this Agreement by the
Company and the Indemnitee shall not in any way limit or affect the rights and obligations of the Company or the other party or parties
thereto under any such Indemnification Arrangement.


 


(c) To the extent that the Company maintains
an insurance policy or policies providing liability insurance for directors, officers, trustees, partners, managers, managing members,
fiduciaries, employees, or agents of the Company or of any other Enterprise which such person serves at the request of the Company, Indemnitee
shall be covered by such policy or policies in accordance with its or their terms to the maximum extent of the coverage available for
any such director, officer, trustee, partner, manager, managing member, fiduciary, employee or agent under such policy or policies. If,
at the time the Company receives notice from any source of a Proceeding as to which Indemnitee is a party or a participant (as a witness,
deponent or otherwise), the Company has director and officer liability insurance in effect, the Company shall give prompt notice of such
Proceeding to the insurers in accordance with the procedures set forth in the respective policies. The Company shall thereafter take all
necessary or desirable action to cause such insurers to pay, on behalf of the Indemnitee, all amounts payable as a result of such Proceeding
in accordance with the terms of such policies.


 


(d) In the event of any payment under
this Agreement, the Company shall be subrogated to the extent of such payment to all of the rights of recovery of Indemnitee, who shall
execute all papers required and take all action necessary to secure such rights, including execution of such documents as are necessary
to enable the Company to bring suit to enforce such rights. No such payment by the Company shall be deemed to relieve any insurer of its
obligations.


 









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(e) The Company’s obligation to
indemnify, hold harmless, exonerate or advance Expenses hereunder to Indemnitee who is or was serving at the request of the Company as
a director, officer, trustee, partner, managing member, fiduciary, employee or agent of any other Enterprise shall be reduced by any amount
Indemnitee has actually received as indemnification, hold harmless or exoneration payments or advancement of expenses from such Enterprise.
Notwithstanding any other provision of this Agreement to the contrary except for Section 27, (i) the Indemnitee shall have no obligation
to reduce, offset, allocate, pursue or apportion any indemnification, hold harmless, exoneration, advancement, contribution or insurance
coverage among multiple parties possessing such duties to Indemnitee prior to the Company’s satisfaction and performance of all
its obligations under this Agreement, and (ii) the Company shall perform fully its obligations under this Agreement without regard to
whether Indemnitee holds, may pursue or has pursued any indemnification, advancement, hold harmless, exoneration, contribution or insurance
coverage rights against any person or entity other than the Company.


 


(f) Notwithstanding anything contained
herein, the Company is the primary indemnitor, and any indemnification or advancement obligation of any Co-Sponsor or its respective affiliates
or any other Person is secondary.


 


	17.	DURATION OF AGREEMENT. All agreements and obligations of the Company contained herein shall continue during the period Indemnitee serves as a director or officer of the Company or as a director, officer, trustee, partner, manager, managing member, fiduciary, employee or agent of any other corporation, partnership, joint venture, trust, employee benefit plan or other Enterprise which Indemnitee serves at the request of the Company and shall continue thereafter so long as Indemnitee shall be subject to any possible Proceeding (including any rights of appeal thereto and any Proceeding commenced by Indemnitee pursuant to Section 14 of this Agreement) by reason of his Corporate Status, whether or not he is acting in any such capacity at the time any liability or expense is incurred for which indemnification or advancement can be provided under this Agreement.
	18.	SEVERABILITY. If any provision or provisions of this Agreement shall be held to be invalid, illegal or unenforceable for any reason whatsoever: (a) the validity, legality and enforceability of the remaining provisions of this Agreement (including, without limitation, each portion of any Section, paragraph or sentence of this Agreement containing any such provision held to be invalid, illegal or unenforceable, that is not itself invalid, illegal or unenforceable) shall not in any way be affected or impaired thereby and shall remain enforceable to the fullest extent permitted by law; (b) such provision or provisions shall be deemed reformed to the extent necessary to conform to applicable law and to give the maximum effect to the intent of the parties hereto; and (c) to the fullest extent possible, the provisions of this Agreement (including, without limitation, each portion of any Section, paragraph or sentence of this Agreement containing any such provision held to be invalid, illegal or unenforceable, that is not itself invalid, illegal or unenforceable) shall be construed so as to give effect to the intent manifested thereby.



 






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	19.	ENFORCEMENT AND BINDING EFFECT.


 


(a) The Company expressly confirms and
agrees that it has entered into this Agreement and assumed the obligations imposed on it hereby in order to induce Indemnitee to serve
as a director, officer or key employee of the Company, and the Company acknowledges that Indemnitee is relying upon this Agreement in
serving as a director, officer or key employee of the Company.


 


(b) Without limiting any of the rights
of Indemnitee under the Charter or Bylaws as they may be amended from time to time, this Agreement constitutes the entire agreement between
the parties hereto with respect to the subject matter hereof and supersedes all prior agreements and understandings, oral, written and
implied, between the parties hereto with respect to the subject matter hereof.


 


(c) The indemnification, hold harmless,
exoneration and advancement of expenses rights provided by or granted pursuant to this Agreement shall be binding upon and be enforceable
by the parties hereto and their respective successors and assigns (including any direct or indirect successor by purchase, merger, consolidation
or otherwise to all or substantially all of the business or assets of the Company), shall continue as to an Indemnitee who has ceased
to be a director, officer, employee or agent of the Company or a director, officer, trustee, general partner, manager, managing member,
fiduciary, employee or agent of any other Enterprise at the Company’s request, and shall inure to the benefit of Indemnitee and
his or her spouse, assigns, heirs, devisees, executors and administrators and other legal representatives.


 


(d) The Company shall require and cause
any successor (whether direct or indirect by purchase, merger, consolidation or otherwise) to all, substantially all or a substantial
part, of the business and/or assets of the Company, by written agreement in form and substance satisfactory to the Indemnitee, expressly
to assume and agree to perform this Agreement in the same manner and to the same extent that the Company would be required to perform
if no such succession had taken place.


 


(e) The Company and Indemnitee agree
herein that a monetary remedy for breach of this Agreement, at some later date, may be inadequate, impracticable and difficult of proof,
and further agree that such breach may cause Indemnitee irreparable harm. Accordingly, the parties hereto agree that Indemnitee may enforce
this Agreement by seeking, among other things, injunctive relief and/or specific performance hereof, without any necessity of showing
actual damage or irreparable harm and that by seeking injunctive relief and/or specific performance, Indemnitee shall not be precluded
from seeking or obtaining any other relief to which he or she may be entitled. The Company and Indemnitee further agree that Indemnitee
shall be entitled to such specific performance and injunctive relief, including temporary restraining orders, preliminary injunctions
and permanent injunctions, without the necessity of posting bonds or other undertakings in connection therewith. The Company acknowledges
that in the absence of a waiver, a bond or undertaking may be required of Indemnitee by the Delaware Court, and the Company hereby waives
any such requirement of such a bond or undertaking.


 






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	20.	MODIFICATION AND WAIVER. No supplement, modification or amendment of this Agreement shall be binding unless executed in writing by the parties hereto. No waiver of any of the provisions of this Agreement shall be deemed or shall constitute a waiver of any other provisions of this Agreement nor shall any waiver constitute a continuing waiver.
	21.	NOTICES. All notices, requests, demands and other communications under this Agreement shall be in writing and shall be deemed to have been duly given (i) if delivered by hand and receipted for by the party to whom said notice or other communication shall have been directed, or (ii) if mailed by certified or registered mail with postage prepaid, on the third (3rd) business day after the date on which it is so mailed:


 


(a) If to Indemnitee, at the address
indicated on the signature page of this Agreement, or such other address as Indemnitee shall provide in writing to the Company.


 


(b) If to the Company, to:


 


CleanTech Acquisition Corp.

207 West 25th Street, 9th Floor

New York, NY 10001

Attn: Eli Spiro, Chief Executive Officer


 


or to any other address as may have been furnished
to Indemnitee in writing by the Company.


 


	22.	APPLICABLE LAW AND CONSENT TO JURISDICTION. This Agreement and the legal relations among the parties shall be governed by, and construed and enforced in accordance with, the laws of the State of Delaware, without regard to its conflict of laws rules. Except with respect to any arbitration commenced by Indemnitee pursuant to Section 14(a) of this Agreement, the Company and Indemnitee hereby irrevocably and unconditionally: (a) agree that any action or proceeding arising out of or in connection with this Agreement shall be brought only in the Delaware Court and not in any other state or federal court in the United States of America or any court in any other country; (b) consent to submit to the exclusive jurisdiction of the Delaware Court for purposes of any action or proceeding arising out of or in connection with this Agreement; (c) waive any objection to the laying of venue of any such action or proceeding in the Delaware Court; and (d) waive, and agree not to plead or to make, any claim that any such action or proceeding brought in the Delaware Court has been brought in an improper or inconvenient forum, or is subject (in whole or in part) to a jury trial.
	23.	IDENTICAL COUNTERPARTS. This Agreement may be executed in one or more counterparts, each of which shall for all purposes be deemed to be an original but all of which together shall constitute one and the same Agreement. Only one such counterpart signed by the party against whom enforceability is sought needs to be produced to evidence the existence of this Agreement.
	24.	MISCELLANEOUS. Use of the masculine pronoun shall be deemed to include usage of the feminine pronoun where appropriate. The headings of the paragraphs of this Agreement are inserted for convenience only and shall not be deemed to constitute part of this Agreement or to affect the construction thereof.










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	25.	PERIOD OF LIMITATIONS. No legal action shall be brought and no cause of action shall be asserted by or in the right of the Company against Indemnitee, Indemnitee’s spouse, heirs, executors or personal or legal representatives after the expiration of two years from the date of accrual of such cause of action, and any claim or cause of action of the Company shall be extinguished and deemed released unless asserted by the timely filing of a legal action within such two-year period; provided, however, that if any shorter period of limitations is otherwise applicable to any such cause of action such shorter period shall govern.
	26.	ADDITIONAL ACTS. If, for the validation of any of the provisions in this Agreement any act, resolution, approval or other procedure is required, the Company undertakes to cause such act, resolution, approval or other procedure to be affected or adopted in a manner that will enable the Company to fulfill its obligations under this Agreement.
	27.	WAIVER OF CLAIMS TO TRUST ACCOUNT. Notwithstanding anything to the contrary contained herein, Indemnitee hereby agrees that he or she does not have any right, title, interest or claim of any kind (each, a “Claim”) in or to any monies in the trust account established in connection with the Company’s initial public offering for the benefit of the Company and holders of shares issued in such offering, and hereby waives any Claim he or she may have in the future as a result of, or arising out of, any services provided to the Company and will not seek recourse against such trust account for any reason whatsoever. For purposes of clarity, Indemnitee acknowledges and agrees that no monies held in the Trust Account may be used to indemnify Indemnitee for any purpose whatsoever.
	28.	MAINTENANCE OF INSURANCE. The Company shall use commercially reasonable efforts to obtain and maintain in effect during the entire period for which the Company is obligated to indemnify the Indemnitee under this Agreement, one or more policies of insurance with reputable insurance companies to provide the officers/directors of the Company with coverage for losses from wrongful acts and omissions and to ensure the Company’s performance of its indemnification obligations under this Agreement. The Indemnitee shall be covered by such policy or policies in accordance with its or their terms to the maximum extent of the coverage available for any such director or officer under such policy or policies. In all such insurance policies, the Indemnitee shall be named as an insured in such a manner as to provide the Indemnitee with the same rights and benefits as are accorded to the most favorably insured of the Company’s directors and officers.





 


(Signatures follow.)


 




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IN WITNESS WHEREOF,
the parties hereto have caused this Agreement to be signed as of the day and year first above written.


 


	 	CLEANTECH ACQUISITION CORP.
	 	 
	 	By:	 
	 	 	Name:	Eli Spiro
	 	 	Title:	Chief Executive Officer
	 	 	 	 
	 	INDEMNITEE
	 	 
	 	By:	 
	 	 	[_____________]


 





[Signature Page to Indemnity Agreement]