According to The New York Times report, the E.P.A believes these cars -- Volkswagen and Audi models sold between 2009 and now -- emit nitrogen oxide, which contributes to smog and serious respiratory problems, in way higher quantities than the carmaker is letting on. While an official investigation is underway, the call-back sends a strong message home to automakers. "Using a defeat device in cars to evade clean air standards is illegal and a threat to public health," Cynthia Giles, the assistant administrator for the Office of Enforcement and Compliance, told the Times. "Working closely with the California Air Resources Board, E.P.A. is committed to making sure that all automakers play by the same rules. E.P.A. will continue to investigate these very serious violations."

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