Test question using VW TDI cars

You purchased a VW TDI car because you need to drive once in a while but also care about the planet. You like the power AND the fuel efficiency too. VW however undermined your efforts by programming a cheat code that makes the diesel burn clean only when tested. It burns 4 to 40x the pollutants it should the rest of the time when you drive it. You are thinking about practical ecology and the niche. VW violated this principle. Explain the principle of niche and how it was used by this company to unethically sell more cars.