Källor: Tysk toppolitiker lät VW stryka i kritiskt tal

Stephan Weil, född 15 december 1958 i Hamburg, Västtyskland, är en tysk socialdemokratisk politiker tillhörande partiet SPD. Han är sedan 19 februari 2013 förbundslandet Niedersachsens ministerpresident (delstatsregeringschef). I denna roll var han även 2013–2014 ordförande för Tysklands förbundsråd och därmed Tysklands förbundspresidents ställföreträdare. Weil är parallellt med ministerpresidentskapet även ordförande för SPD-distriktet i Niedersachsen. Han var tidigare, från november 2006 till januari 2013, överborgmästare i förbundslandet Niedersachsens huvudstad Hannover.

The Volkswagen emissions scandal (also called "emissionsgate" or "dieselgate") started on 18 September 2015, when the United States Environmental Protection Agency (EPA) issued a notice of violation of the Clean Air Act to German automaker Volkswagen Group. The agency had found that Volkswagen had intentionally programmed turbocharged direct injection (TDI) diesel engines to activate some emissions controls only during laboratory emissions testing. The programming caused the vehicles' NOx output to meet US standards during regulatory testing but emit up to 40 times more NOx in real-world driving. Volkswagen deployed this programming in about eleven million cars worldwide, and 500,000 in the United States, during model years 2009 through 2015. The findings stemmed from a study on emissions discrepancies between European and US models of vehicles commissioned in 2014 by the International Council on Clean Transportation (ICCT), summing up the data from three different sources on 15 vehicles. Among the research groups was a group of five scientists at West Virginia University, who detected additional emissions during live road tests on two out of three diesel cars. ICCT also purchased data from two other sources. The new road testing data and the purchased data were generated using Portable Emissions Measurement Systems (PEMS) developed by multiple individuals in the mid-late 1990's. The findings were provided to the California Air Resources Board (CARB) in May 2014. Volkswagen became the target of regulatory investigations in multiple countries, and Volkswagen's stock price fell in value by a third in the days immediately after the news. Volkswagen Group CEO Martin Winterkorn resigned, and the head of brand development Heinz-Jakob Neusser, Audi research and development head Ulrich Hackenberg, and Porsche research and development head Wolfgang Hatz were suspended. Volkswagen announced plans to spend US$7.3 billion (later raised to €16.2 billion, US$18.32 billion) on rectifying the emissions issues, and planned to refit the affected vehicles as part of a recall campaign. The scandal raised awareness over the higher levels of pollution being emitted by all vehicles built by a wide range of car makers, which under real world driving conditions are prone to exceed legal emission limits. A study conducted by ICCT and ADAC showed the biggest deviations from Volvo, Renault, Jeep, Hyundai, Citroën and Fiat, resulting in investigations opening into other potential diesel emissions scandals. A discussion was sparked on the topic of software-controlled machinery being generally prone to cheating, and a way out would be to open source the software for public scrutiny. On April 21, 2017, a US federal judge ordered Volkswagen "to pay a $2.8 billion criminal fine for rigging diesel-powered vehicles to cheat on government emissions tests." The "unprecedented" plea deal formalized a punishment that Volkswagen AG agreed to earlier in 2017.