Volkswagen's 'Dieselgate' emissions scandal

In September 2015, the US Environmental Protection Agency issued a notice of violation revealing that Volkswagen had installed 'defeat device' software in diesel engines across millions of vehicles worldwide, software designed to detect when a car was undergoing official emissions testing and temporarily reduce pollution output, only to revert to normal, far higher emissions during regular driving. Real-world nitrogen oxide emissions from the affected vehicles were found to be up to 40 times above the legal limit, undermining years of Volkswagen marketing that had promoted its diesel engines as clean and efficient. The company admitted the deception affected roughly 11 million vehicles globally, and the fallout proved enormous: Volkswagen ultimately paid more than $30 billion in fines, vehicle buybacks and settlements in the United States alone, its chief executive resigned within days of the EPA's announcement, and several executives faced criminal charges in Germany and the US. The scandal also prompted a broader regulatory crackdown on diesel-emissions testing across Europe and accelerated the auto industry's shift toward electric vehicles.