(CDTI) Receives EPA Verifications for Purifilter®EGR, Purifilter®OR

VENTURA, Calif., Dec. 19, 2013 — Clean Diesel Technologies, Inc. (Nasdaq:CDTI) (“CDTi”), a leader in advanced emissions control solutions, is pleased to announce that it has received two significant emission reduction product verifications from the U.S. Environmental Protection Agency (the “EPA”) for use in heavy duty highway truck engines and off-road engines.

The uniquely designed Purifilter®EGR, featuring CDTi’s proprietary MPC® technology, is a passively-regenerating diesel particulate filter that provides exceptional filtration and regeneration efficiency for the removal of particulate matter. The EPA first verified Purifilter®EGR for 2002-2010 heavy duty highway truck engines in November 2012. In October 2013, the EPA extended the verification to cover all exhaust gas recirculation (“EGR”) and non-EGR heavy duty highway engines certified with particulate matter emissions at or below 0.1 g/hp-hr manufactured between 1993 and 2010. This extension of the Purifilter®EGR verification means that it can now be applied to the vast majority of heavy duty highway engines sold over the past twenty years.

In December 2013, the EPA verified Purifilter®OR for Tier 1 thru Tier 3 (1996 to 2012) off-road engines with power ratings from 100 to 603hp and certified with particulate matter emissions values of 0.2 g/hp-hr or less. The Purifilter®OR is the off-road version of Purifilter®EGR. The EPA has recently announced a $2 million funding for a 2013 construction equipment rebate program. In addition, the EPA has announced the availability of $4 million in DERA funding for clean diesel projects at ports. CDTi’s Purifilter®EGR and Purifilter®OR may now be employed by fleets under these EPA funded programs in addition to CDTi’s other EPA and Air Resources Board verified diesel emission reduction products.

“With EPA verification granted, CDTi can assist highway and off-road fleet managers to broadly retrofit their vehicles with passively regenerating diesel particulate filters in order to reduce particulate matter emissions in excess of 90%. With our extensive retrofit experience and large distributor network, we are absolutely committed to addressing this larger market opportunity,” said Ian MacDonald, Vice President, Sales & Marketing for CDTi.

About CDTi

CDTi is a vertically integrated global manufacturer and distributor of emissions control systems and products, focused on the heavy duty diesel and light duty vehicle markets. CDTi utilizes its proprietary patented Mixed Phase Catalyst (MPC®) technology, as well as its ARIS® selective catalytic reduction, Platinum Plus® fuel-borne catalyst, and other technologies to provide high-value sustainable solutions to reduce emissions, increase energy efficiency and lower the carbon intensity of on- and off-road engine applications. CDTi is headquartered in Ventura, California and currently has operations in the U.S., Canada, France, Japan and Sweden. For more information, please visit www.cdti.com.

Forward-Looking Statements Safe Harbor

Certain information contained in this press release constitutes forward-looking statements. Any statements contained herein that are not statements of historical fact should be considered forward-looking statements. You can identify these forward-looking statements by the use of words such as “believe(s)”, “expect(s)”, “anticipate(s)”, “plan(s)”, “may”, “will”, “would”, “intend(s)”, “estimate(s)” or similar expressions, as well as other words or expressions referencing future events, conditions or circumstances, whether in the negative or affirmative. Examples of forward-looking statements contained in this press release include, among others, statements regarding potential uses for CDTi’s Purifilter®EGR, the availability of EPA-announced funding, the use of CDTI’s Purifilter®EGR and Purifilter®OR by fleets under EPA-funded programs, the anticipated benefits of receiving EPA verification, and CDTi’s plans with respect to addressing market opportunities. Forward-looking statements are based on a series of expectations, assumptions, estimates and projections which involve substantial uncertainty and risk. In general, actual results may differ materially from those indicated by such forward-looking statements as a result of risks and uncertainties, including, but not limited to, the potential future unavailability of government funding, unforeseen difficulties in applying Purifilter®EGR or Purifilter®OR to heavy duty highway engines or fleets under EPA funded programs, unforeseen difficulties in achieving sales despite the potential applicability of CDTi’s products, and other risks and uncertainties discussed or referenced in CDTi’s Annual Report on Form 10-K filed on March 27, 2013 and other filings with the Securities and Exchange Commission. In addition, any forward-looking statements represent CDTi’s estimates only as of the date such statements and should not be relied upon as representing CDTi’s estimates as of any subsequent date. CDTi specifically disclaims any obligation to update forward-looking statements. All forward-looking statements in this press release are qualified in their entirety by this cautionary statement.

CONTACT: Kevin M. McGrath
         Cameron Associates, Inc.
         Tel:  +1 (212) 245-4577