In Europe: “diesel has been favored by public policy because it produces less carbon emissions than petrol, and is therefore better in the fight against climate change. But diesel produces far more air pollution – up to 15 times more than petrol (or unleaded gasoline).”
“The French and British capitals are grappling with dangerous levels of air pollution this week – conditions in winter help smog stick around. The mayor of Paris wants to ban diesel cars to stem it. Will London follow?”
http://www.dw.com/en/paris-takes-on-winter-smog/a-36663652
Remember, this is all going on at the same time the UK is building diesel farms to save their electricity grid from the stupid decision to rely on wind.
sunshine hours 
“But diesel produces far more air pollution – up to 15 times more than petrol (or unleaded gasoline)”
According to EPA computer
gamesmodels, I understand.And remember that down in South Australia farmers and industry and installing diesel back up generators because the power from their wind farms is so unreliable.
Diesel exhaust can be cleaned up as has been done on the trucks but it’s expensive and bulky equipment. I drive a Freightliner Cascadia with a DD 13 engine and they claim the pollution control system reduces emissions to the point that the exhaust is cleaner than the average ambient air quality in most large cities.