Since Volkswagen’s “dieselgate” emissions cheating scandal broke last year and set anti-diesel sentiment dominoes to tumbling, antipathy for oil-burning engines has increased, and now four cities have vowed to ban them by 2025.

Announced Friday in Mexico City at the sixth biennial C40 Mayors Summit, the mayors of Paris, Mexico City, Madrid and Athens said the countdown timer is now ticking for the day diesels would be forbidden in their jurisdictions.

Citing concerns for general air quality and an agenda in sympathy with the 2015 Paris Agreement on climate change, the four mayors signed an “Air Quality Declaration” as part of other commitments arising from the summit.

The C40’s organizers call the gathering “a network of the world’s megacities committed to addressing climate change.” Taking the mission seriously, the four mayors pledged to incentivize alternative-energy vehicles while promoting walking and cycling infrastructure.

“Mayors have already stood up to say that the climate change is one of the greatest challenges we face,” said Anne Hidalgo, Mayor of Paris and new Chair of the C40 Cities Climate Leadership Group. “Today, we also stand up to say we no longer tolerate air pollution and the health problems and deaths it causes – particularly for our most vulnerable citizens. Big problems like air pollution require bold action, and we call on car and bus manufacturers to join us.”

Click to enlarge. The state of California has identified 41 toxic air contaminants in diesel exhaust. California defines these as “an air pollutant which may cause or contribute to an increase in mortality or in serious illness, or which may pose a present or potential hazard to human health.”

Click to enlarge. California has identified 41 toxic air contaminants in diesel exhaust. California defines these as “an air pollutant which may cause or contribute to an increase in mortality or in serious illness, or which may pose a present or potential hazard to human health.”

The activist mayors also expressed harmony of view with the World Health Organization (WHO) which says each year 3 million deaths are linked to outdoor air pollution – with the large majority of these deaths occurring in cities.

And, if that is not committed enough, the mayors are asking concerned people everywhere to sign a petition calling on carmakers themselves to quit the diesel market.

The petition does not mince words saying “throughout the world, the motor vehicle industry continues to invest and manufacture vehicles that are known to poison the air the we breathe. 
The motor vehicle industry has an historic opportunity: Get serious about air pollution to save people and the planet.”

SEE ALSO: Volkswagen Embraces EVs So You’ll Forget Dieselgate
In all, the move signals handwriting on the wall for diesels. Even before the VW cheating scandal, advocates had called for a ban on diesels in places, including London. Ironically, modern exhaust-cleaning aftertreatment technology is – despite cheaters – capable of scrubbing emissions to levels comparable with modern gas-burning engines.

Of concern however is not just the latest, greatest diesels, but older, and out of compliance diesels, larger vehicles not held to as high a standard, and even vehicles willfully modified for more power at the expense of emissions.

It would appear also that sentiment is also adding momentum to the fervor in certain quarters, especially now that clearly cleaner alternatives are more favored.

Preferred are electrified vehicles, which would help alleviate conditions along with other measures being taken by the four mayors.

“It is no secret that in Mexico City, we grapple with the twin problems of air pollution and traffic,” said Mayor of Mexico City, Miguel Ángel Mancera. “By expanding alternative transportation options like our Bus Rapid Transport and subway systems, while also investing in cycling infrastructure, we are working to ease congestion in our roadways and our lungs.”

Early morning emissions in London. © Simon Birkett 2014.

Early morning emissions in London. © Simon Birkett 2014.

The Mayor of Madrid Manuela Carmena, concurred, and the mayors say decarbonizing of transportation systems while promoting alternative transportation options dovetails with ambitions of the Paris Agreement.

“The quality of the air that we breathe in our cities is directly linked to tackling climate change,” said Carmena. “As we reduce the greenhouse gas emissions generated in our cities, our air will become cleaner and our children, our grandparents and our neighbors will be healthier.”

Update: A Spanish-language report says Carmena’s team denied signing the agreement. (If you don’t read Spanish – see Google Translate)


And if removal of diesels is not enough, Mayor of Athens, Giorgos Kaminis said the goal there is to go further.

“Our goal is to ultimately remove all cars from the centre of Athens in the years to come,” Kaminis. “I support the bold ambition of the Air Quality Declaration and call on our partners in the national government to implement their commitments based on the international climate action agreements and to join our common effort to clean the air that we breathe.”

Among other actions, C40 announced also it was joining with the WHO and UN Environment’s Climate and Clean Air Coalition, in support of the BreathLife campaign to halve the 6.5 million deaths from air pollution by 2030.


This is a global campaign to help city governments reduce emissions from the transport, waste, and energy sectors, and to enable the mobilization of citizen action to cut air pollution and slow climate change.

“Ninety two percent of the world’s population live in places where air pollution levels exceed the WHO safe level for air pollution. Soot from diesel vehicles are amongst the big contributors to ill health and global warming. But we have many solutions that work,” said Helena Molin Valdés, Head of the CCAC. “By working with C40 cities and other partners, we can help cities work together, identify and implement the most effective solutions to rapidly improve air quality and achieve the BreatheLife goal to halve deaths from air pollution by 2030.”