Diesel cars have dominated Europe for decades, but recently a major backlash against them has started to brew.
Politicians and advocacy groups in several European countries are taking strong steps to limit or eliminate older, dirtier diesels, over concerns of negative health effects from their particulate emissions.
So even as carmakers roll out new models that comply with stricter Euro 6 emissions standards, some parts of the public are starting to turn against diesel.
That's led several major carmakers to support a campaign to counteract the "creeping demonization of diesel," in the words of the Financial Times.
2016 Land Rover Range Rover and Range Rover Sport HSE Td6 diesel models, 2015 Detroit Auto Show
BMW, Ford, Jaguar Land Rover, and Volkswagen are among the companies that have signed on to the campaign, which argues that current perception of diesel is unfairly focused on the oldest models.
The Euro 6 standards that take effect this year are roughly equivalent to the U.S. Tier II, Bin 5 standards adopted in 2007; they dramatically cut emissions of nitrogen oxides (NOx) and particulate matter.
Ironically, the implementation of these standards come at virtually the same time as increased public concern over pollution from the older diesel vehicles the standards will make obsolete.
The north London borough of Islington recently introduced a parking surcharge for diesel vehicles, and a second borough--Hackney--is reportedly considering a similar policy.
The London city government also plans to introduce an "ultra-low emissions zone," which would nearly double the British capital's congestion charge for older diesel vehicles.
Toyota Prius Plug-In Hybrid prototype in London, U.K.
Last summer, NOx levels in London surpassed those even in the legendarily polluted air of Beijing, and the city faces fines from the European Union if it fails to meet air-quality targets.
As in other European countries reconsidering their reliance on diesel, this marks a major policy shift in the U.K.
ALSO SEE: Are Diesel Cars In Europe Starting A Long Slow Decline? (Mar 2013)
Policymakers had promoted diesel cars as a green alternative to gasoline for years because of their superior fuel economy, and policies gave diesel fuel a tax advantage over gasoline.
As a result, the portion of diesel cars on U.K. roads rose from around 1 percent in 1984 to roughly one-third of the total number of vehicles in 2014.
Diesels represent roughly half of new passenger-vehicle sales in the European Union as a whole.