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Exhibit 21

SUBSIDIARIES OF REGISTRANT

        Clean Diesel Technologies, Inc.'s subsidiaries as of December 31, 2015 are listed below.

Name of Subsidiary	State/Jurisdiction of Incorporation	Common Equity Ownership
Clean Diesel Technologies Limited	United Kingdom		100	%
Catalytic Solutions, Inc.	California		100	%
CSI Aliso, Inc.	California		100	%
Catalytic Solutions Holdings, Inc.	Delaware		100	%
ECS Holdings, Inc.	Delaware		100	%
Engine Control Systems Ltd.	Nevada		100	%
Engine Control Systems Limited	New Brunswick		100	%
CDTI Sweden AB	Sweden		100	%

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Exhibit 21

SUBSIDIARIES OF REGISTRANT