Today, diesel engines are known to be heavy-duty, hardworking engines, most commonly found in heavy machinery. But their reputation for being fuel efficient made them a once popular choice for cars across parts of the world. Then the case for diesel seemed to crash in the 90s, when global health authorities determined diesel to be carcinogenic. » Subscribe to CNBC: https://cnb.cx/SubscribeCNBC » Subscribe to CNBC TV: https://cnb.cx/SubscribeCNBCtelevision » Subscribe to CNBC Classic: https://cnb.cx/SubscribeCNBCclassic About CNBC: From 'Wall Street' to 'Main Street' to award winning original documentaries and Reality TV series, CNBC has you covered. Experience special sneak peeks of your favorite shows, exclusive video and more. Connect with CNBC News Online Get the latest news: https://www.cnbc.com/ Follow CNBC on LinkedIn: https://cnb.cx/LinkedInCNBC Follow CNBC News on Facebook: https://cnb.cx/LikeCNBC Follow CNBC News on Twitter: https://cnb.cx/FollowCNBC Follow CNBC News on Instagram: https://cnb.cx/InstagramCNBC #CNBC Why Diesel Cars Are Disappearing