Volkswagen's emissions scandal involved the installation of 'defeat devices' in approximately 11 million diesel vehicles to cheat emissions tests, resulting in cars that emitted pollutants far exceeding legal limits under normal driving conditions. The scandal was uncovered by researchers at West Virginia University in 2014, leading to significant legal and financial repercussions for Volkswagen, including a criminal investigation and potential fines exceeding $18 billion. The Environmental Protection Agency plans to enhance testing standards in response to the incident, particularly regarding the oversight of automotive software.