Newly shipped Volkswagen vehicles sit on a back lot at a Volkswagen dealership in San Diego, California September 23, 2015. Volkswagen Chief Executive Martin Winterkorn resigned on Wednesday, succumbing to pressure for change at the German carmaker, which is reeling from the admission that it deceived U.S. regulators about how much its diesel cars pollute. REUTERS/Mike Blake

Volkswagen Group CEO Martin Winterkorn resigned on Wednesday amid scandals surrounding “defeat devices” which switched car engines to a cleaner mode to deceive U.S. emission testing. The German automaker came under mounting pressure to take a decisive action while its share prices plummeted down by more than 30 percent since the scandal started making headlines.

"Volkswagen needs a fresh start -- also in terms of personnel. I am clearing the way for this fresh start with my resignation," the Reuters quoted Winterkorn as saying. He had held a marathon of meetings before reaching the decision.

The biggest carmaker of the world, touted for its quality, efficiency and reliability, conceded to U.S. regulators that the cars manufactured by it are designed to trick emission tests. It also said that the software may have been installed on as many as 11 million cars manufactured by it.

The software used in the cars could detect when they are being tested and switch the diesel engines to a cleaner mode. This implied that the true emissions by these cars could be hidden to a level over 40 times of what is legally allowed by U.S. standards.

Winterkorn though said he accepted the responsibilities of the irregularities found in the diesel engines but clarified he was not aware of any malpractice.

The Volkswagen group has not yet announced Winterkorn’s successor. But it has said that the decision would be taken over a full board meeting on Friday. However, those seen as the most possible choice for the next VW chief are Matthias Muller, the CEO of Porsche; Herbert Diess, the head of the VW brand; and Audi CEO Rupert Stadler.

Mexico also had announced investigations into the matter to check whether the car manufacturer, which produces the diesel versions of Jetta, Beetle and Golf in a large plant in Puebla, has been tricking its regulators as well.

Winterkorn, the outgoing chief of VW, headed the company for eight long years and oversaw the company tripling its profits and swelling up its sales to double. "I am shocked by the events of the past few days. Above all, I am stunned that misconduct on such a scale was possible in the Volkswagen Group,” he said in a statement.

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