On January 27, 2017, US Customs and Border Protection (CBP) published in the Federal Register a document [USCBP–2016–0011; CBP Dec. 16–29] delaying the effective date of the final rule published in the Federal Register on December 27, 2016 announcing amendments to CBP regulations relating to the importation into the United States of certain vehicles and engines under the Clean Air Act (CAA) in order to harmonize the documentation requirements applicable to different classes of vehicles and engines that are subject to the CAA’s emission standards. That document further amended the regulations to permit importers to file the required U.S. Environmental Protection Agency (EPA) Declaration Forms with CBP electronically, and amended non-substantive provisions to update regulatory citations and delete obsolete provisions. The changes announced in that final rule were to be effective January 26, 2017. This notice announces that the effective date of the final rule The effective date of the rule amending 19 C.F.R. part 12 published at 81 Fed. Reg. 94974, on December 27, 2016 is delayed until March 21, 2017, in accordance with the White House Chief of Staff’s memorandum of January 20, 2017.