1) Volkswagen was found to have installed illegal "defeat device" software in 11 million diesel vehicles worldwide to cheat emissions tests.
2) The software could detect test scenarios and put engines into a low-power mode to reduce emissions during tests.
3) Volkswagen faces fines up to $18 billion in the US and long-term damage to its reputation and brand trust. Other carmakers may face increased scrutiny over emissions testing practices.
4) The scandal has major implications for Volkswagen and the auto industry, with consumers potentially losing trust in diesel vehicles and manufacturers.