<PAGE>

                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549


                               Amendment No. 1 to

(Mark One)
[X]   ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE
      ACT OF 1934 [NO FEE REQUIRED]

                  For the fiscal year ended: December 31, 1996
                                       OR
[   ] TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 (d) OF THE SECURITIES
      EXCHANGE ACT OF 1934 [NO FEE REQUIRED]

    For the transition period from __________________ to ____________________

                           Commission File No. 0-27432

                         CLEAN DIESEL TECHNOLOGIES, INC.
--------------------------------------------------------------------------------
             (Exact name of registrant as specified in its charter)

<TABLE>
<S>                                                                  <C>       
              Delaware                                                             06-1393453
--------------------------------------------------------------       ---------------------------------------
(State or other jurisdiction of incorporation of organization)       (I.R.S. Employer Identification Number)
</TABLE>

                         Suite 702, 300 Atlantic Street
                               Stamford, CT 06901
                                 (203) 327-7050
          -------------------------------------------------------------
          (Address and telephone number of principal executive offices)

        Securities registered pursuant to Section 12(b) of the Act: None

          Securities registered pursuant to Section 12 (g) of the Act:

                     Common Stock $0.05 par value per share
                     --------------------------------------

                                (Title of Class)

Indicate by check mark whether the registrant: (1) has filed all reports
required to be filed by Section 13 or 15(d) of the Securities Exchange Act of
1934 during the preceding 12 months (or for such shorter period that the
registrant was required to file such reports), and (2) has been subject to such
filing requirements for the past 90 days.

                                Yes  X  No
                                    ---    ---

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405
of Regulation S-K is not contained herein, and will not be contained, to the
best of the registrant's knowledge, in definitive proxy or information
statements incorporated by reference in Part III of this Form 10-K or any
amendment to this Form 10-K. [ ]

Aggregate market value of the voting stock held by non-affiliates of the
registrant based on the average bid and asked prices of March 18, 1997:
$10,695,830.

Indicate number of shares outstanding of each of the registered classes of
common stock at March 18, 1997: 2,516,666 shares Common Stock, $0.05 par value.

                      Documents incorporated by reference:
Certain portions of the registrant's 1996 Annual Report to stockholders and of
the registrant's Proxy Statement for the annual meeting of stockholders to be
held in 1997 described in Parts II, III, and IV hereof are incorporated by
reference in this report.



<PAGE>


                                     Part IV


Item 14. Exhibits, Financial Statement Schedules and Reports on Form 8-K.

(a). (3)  Exhibits


          EXHIBIT NO.   TITLE        
          ------- ---   -----        


              27        Financial Data Schedule







































                                        2


<PAGE>




                                   SIGNATURES

         Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, Clean Diesel Technologies, Inc. has duly caused this
Amendment No. 1 to Report on Form 10-K to be signed on its behalf by the
undersigned, thereunto duly authorized.

                                         CLEAN DIESEL TECHNOLOGIES, INC.



          May 5, 1997                   By:   /s/ Jeremy D. Peter-Hoblyn
      ------------------                       --------------------------
            Date                               Jeremy D. Peter-Hoblyn
                                               Chief Executive Officer,
                                               President and Director


         Pursuant to the requirements of the Securities Exchange Act of 1934,
this Amendment No. 1 to Report on Form 10-K has been duly signed below by the
following persons on behalf of Clean Diesel Technologies, Inc. and in the
capacities and on the dates indicated.


<TABLE>
<S>                                <C>                                                  <C> 
     /s/ Ralph E. Bailey           Director and Chairman of the Board of Directors      May 5, 1997
     -------------------------
         Ralph E. Bailey


     /s/ Jeremy D. Peter-Hoblyn    Chief Executive Officer, President and Director      May 5, 1997
     -------------------------     (principal executive officer)
         Jeremy D. Peter-Hoblyn    


     /s/ Scott M. Schecter         Chief Financial Officer, Vice President and          May 5, 1997
     -------------------------     Treasurer (principal financial and accounting 
         Scott M. Schecter         officer)


     /s/ James M. Valentine        Director, Chief Operating Officer, and               May 5, 1997
     -------------------------     Executive Vice President
         James M. Valentine        


     /s/ Kent D. S. Durr           Director                                             May 5, 1997
     -------------------------
         Kent D. S. Durr


     /s/ John A. de Havilland      Director                                             May 5, 1997
     -------------------------
         John A. de Havilland


     /s/ Charles W. Grinnell       Director, Vice President and Corporate Secretary     May 5, 1997
     -------------------------
         Charles W. Grinnell
</TABLE>

                                       3