The logo of German carmaker Volkswagen is seen on the front grill of a Passat car in Willmette, Illinois, September 24, 2015.
The logo of German carmaker Volkswagen is seen on the front grill of a Passat car in Willmette, Illinois, September 24, 2015. Reuters/Jim Young

Volkswagen violated the U.S. Clean Air Act from 2009 to 2015 and manufactured and installed “defeat devices” in certain models equipped with 2.0 litre engines, said the United States Environmental Protection Agency (EPA).

Volkswagen has admitted “irregularities” in software used to monitor emissions of its diesel engines. Across the globe, the company sold 11 million cars with software that deceived U.S. air pollution regulators. Most of the defective cars are said to be in Europe, including diesel versions of the popular Beetle, Golf, Jetta and Passat.

The company has stopped U.S. sales of its upcoming 2016 clean diesel vehicles because the EPA ordered it to first address the issue and fix millions of cars with the defective monitoring systems.

The German auto maker admitted cheating air pollution tests for years, according to a report in Bloomberg Business. The report said the company could end-up paying $18 billion in fines. The U.S. Department of Justice has also filed criminal charges against Volkswagen.

Audi confirmed that about 2.1 million of its cars have the software that manipulates emission tests. The cars are likely to be recalled and repaired at the earliest. The models include the A1, A3, A4, A5, A6, TT, Q3 and Q5, revealed Jürgen De Graeve, spokesman for Audi AG, reports The Wall Street Journal.

Only 13,000 of these cars were sold in the U.S. and Canada while the rest were sold in Europe. Volkswagen subsidiary, the Czech car maker Skoda, confirmed that about 1.2 million of its cars were also affected.

VW Chief Executive Officer Martin Winterkorn resigned because of the scandal and Volkswagen AG named Matthias Müller, current head of Porsche, as VW’s new CEO. The company also suspended several employees and hired a U.S. law firm to investigate the issue.

“Under my leadership, Volkswagen will do all it can to develop and implement the strictest compliance and governance standards in the whole industry,” said Müller, as reported by Fortune.

In a letter to employees, Müller ensured that he would work towards mending the lost image of the brand and promised to get to the “bottom” of the issue in a fast, open and decisive manner. Volkswagen shares continued to fall, closing 7.46% down on Sept. 28.

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