The C40 Cities Climate Leadership Group is a consortium of 96 cities around the world working to combat air pollution and make the air in our streets more breathable. It is a global network of mayors united against the climate crisis through inclusive, collaborative, and science-based actions to halve emissions by 2030, help the planet limit warming to 1.5 °C, and build healthy, just, and resilient communities. The objectives of this group include building a global movement, through robust advocacy and international diplomacy, to spread climate action on a large scale and share best practices across high-impact sectors.

Among the C40 metropolises, many have already made their mobility more restrictive by limiting the circulation of cars. Others have increased pedestrian spaces and encouraged soft mobility. The recipe is never the same, but the political will is: air pollution has a huge impact on public health, and congested traffic certainly does not help to reduce travel times. According to C40, it is time to change direction: not by improvising, but by relying on proven strategies that can guarantee solid results.

To help cities design their own clean zones, C40 has developed a comprehensive guideline document for administrations and decision-makers, the 'Clean Air Zone Toolbox'. The ways in which low-emission zones, also called clean-air zones, low-traffic zones, traffic-restricted zones, or even zero-emission zones in cases where the passage of cars is completely banned, are varied indeed.

This is evident in the C40 cities themselves: in London, for example, the clean air zone is extensive, operates 24 hours a day, and requires an entry fee. Paris, on the other hand, focuses on increasing cycle lanes and transforming on-street parking spaces into widespread green areas, while Quito has encouraged pedestrianisation and electric cars. In addition to combating emissions, some administrations have taken targeted measures to combat the harmful effects of solid waste combustion, cooking fuels and industrial emissions.

How, then, does one orientate oneself among this wide range of possibilities? C40 suggests, in its toolbox, starting with a fundamental strategic step: the detailed analysis of your needs (assessment). The grid of questions devised by its experts makes it possible to investigate the concrete reality from many angles. What are the main pollutants? How is the local demography distributed? Which population is most exposed to pollutants, and which are the most vulnerable groups most affected by them? How many people depend on a private vehicle for their journeys? And what can the impact of a reduction in traffic access be on the social and economic vitality of a specific area? 

Once data are acquired, awareness deepens and policy choices become more evident: it is the moment for participatory planning, through either citizen involvement or the establishment of focus groups, and for defining policy along with the optimal methods for its implementation.

In this planning phase, the municipality may opt to close an area to traffic or only specific roads. Certain parameters can guide the identification of access criteria: while in some cases all cars may be banned, in others the passage may be restricted to the most polluting vehicles or to all internal combustion vehicles, effectively favouring electric vehicles, including cargo vehicles for goods distribution. Another option is to bet on economic disincentives: a Clear Air Zone can be associated with toll payments, effectively betting on the dissuasive effect of the costs to be incurred. 

Some suggestions concern the criteria for choosing the location of Clear Air Zones. The recommendation, in this case, is to start with the areas where population density and air pollution are highest, so as to maximise the impact on the citizenry and leverage the achievements to capitalise on consensus. Voluntary and incentive-based programmes are not dismissed either, as they are particularly suitable in cases where specific legal constraints prohibit policies based on access restrictions. And because psychology plays its part, C40 suggests not opting for what it calls a 'big bang' approach: it is better not to impose a drastic change, but instead to favour the gradual introduction of selected measures.

Of course, a policy based solely on restricting access opportunities cannot, by itself, win the trust of those citizens who are sceptical about measures that could radically change their daily lives. It is important then, says C40, to compensate for what has been taken away with new services, starting with enhanced public transport, pedestrian and bicycle paths that guarantee safety, and power stations to recharge all electric vehicles. Again, the public sector is called upon to set a good example: there would be little point in adopting policies to decarbonise private transport if, for example, new municipal buses were not electric.

To date, there are 320 Clear Air Zones in Europe. Many other cities, from America to Asia, are active participants in the movement, contributing to the global discussion and exploring how to make use of the expertise that C40 and its community provide. The administrators of the C40 cities meet regularly to exchange guidelines and monitor the measures implemented, so as to continuously adjust the solutions applied on the ground according to their effectiveness. A durable commitment that, as statistics confirm, ultimately wins over citizens despite initial controversies, with polls appearing to endorse the adopted policies from Bogotá to Johannesburg, from London to Seattle and Seoul.

Genoa has far surpassed Rome and Milan in the percentage of free transport and by 2026, it is aiming for the full exploitation of the smart city model, which could mean pedestrianising large areas of the historic centre. The Ligurian capital, thanks to the complete city coverage with dedicated cameras, expects to be able to have widespread control of all entrances to the city.

This step, combined with the goal of full electrification of public transport by 2026, with the construction of interchange car parks and a public transport policy carried out with new electric vehicles, operating schedules with high frequencies, free passes for large groups of users and vehicles or at a price that is 55% less than in the past, should allow a drastic reduction in the number of car entrances. 

One of the main players in this revolution is AMT, the company that manages Genoa's local public transport. It serves the capital and the 66 municipalities of the metropolitan city with metros, buses and trolleybuses, funiculars, lifts, rack railway, Genoa Casella railway and Navebus. The revolution it has carried out has led to the creation of three different annual passes, the most expensive of which costs EUR 295, and the extension of free travel on much of the urban transport. The metro and lifts are free for all residents, while the over 70s and under 14s also ride free on buses and trolleybuses.

AMT is led by Ilaria Gavuglio, who explains the numbers representative of the project's success. “In the first four months of 2023, Genoa had 16,700 subscribed riders per year. By the same date in 2024, there were 46,674. This resulted in an increase in turnover of four million compared to the same period last year, and that is considering that in 2023, the under-14s and over-70s were paying for tickets and annual passes. This is an incredible result, since one of the company's objectives was precisely to cover the increased number of paying subscribers with free tickets.”
 

How many free passes were there? 

“There were 58,500. Paid passes not only fully compensated for this, but also generated an increase in turnover which, I repeat, was not prudently expected. We applied an economic principle: the lower the price, the more demand naturally increases. But we have noticed that the price decrease must be significant. We lowered the cost of passes by 55%. What cost EUR 650 yesterday now costs EUR 295, and this has been the reason for the rapid increase in the number of subscribed riders. The reaction of the users was beyond imagination.”
 

From an environmental point of view, which goals have been achieved so far? You expect to achieve complete electrification of vehicles in 2026, right?

“Yes, that's right. To date, we have 144 electric vehicles, we are ranked first in Italy for the percentage of routes operated with electric vehicles, and our goal is electrifying the entire urban fleet by early 2026. This is possible thanks to the resources made available to us by the administration of the Municipality of Genoa, through the NRRP. AMT started an electrification plan as early as 2019. To date, we have measured the abatement of pollutants at 13% less CO₂ emissions per 100,000 kilometres, 51% less nitrogen oxides (NOx) emissions per 100,000 kilometres, 44% less carbon monoxide emissions and 35% less PM10 emissions. So what does this mean? The more we electrify our fleets, the more we limit the use of private cars, the more we push for an increase in public transport users, the more there is a multiplier effect in reducing these pollutants.”
 

In the future, will you build a series of car parks on the edge of the city to allow non-residents to use your system as well?

“Yes, also because of course it is a project, that of the administration, which is based precisely on the logic of interchange; therefore, users who arrive by car will be able to leave it in the interchange car parks, which will be extended and increased, and then, they will be able to travel by public transport. But let’s not forget, we want public transport to be used not only in the municipality of Genoa but also throughout the entire metropolitan area. Our fare policy is based precisely on this, because we have launched travel passes that are valid throughout the entire metropolitan city. This is the real innovation.”
 

However, this resulted in the price variation of the single ticket to EUR 2, a change that some people did not like, let's say...

“Yes, but there is a fee in expanding the service. In the past, the EUR 1.50 ticket allowed you to travel in the urban area of Genoa only. Today, we offer a EUR 2 ticket, compared to the urban area alone, there has been an 33% increase in value, but in addition to the increase in the service, the company offers much more, both in terms of duration, because we have lengthened it, and in terms of the services that the company offers. So, there is more than just an increase in price, but also an increase in the services offered.