As European cities race to meet the EU’s climate neutrality goals, Cartagena, a Mediterranean port city in Spain, is proving that digital transformation and citizen-centric planning can go hand in hand.

Leveraging AI, IoT, and a Smart City platform co-developed with Libelium, Cartagena is not only complying with national mandates for Low Emission Zones (LEZs), but also rethinking them entirely.

Rethinking LEZs through smart technology

Rather than applying blanket restrictions or vehicle bans, Cartagena took a more nuanced and adaptable route, enabled by technology.

At the centre of this strategy is a solid digital infrastructure, built in collaboration with Libelium. It is powered by the envair360 platform, an advanced simulation and predictive analytics tool that gives city planners insights and foresight to allow for evidence-based decision-making.

The city’s Smart City platform isn’t just about collecting data, it’s about turning that data into practical, real-time insights. With this system in place, Cartagena is proving that it’s possible to develop urban mobility policies that are both effective for the environment and mindful of how people actually live and move around the city.

The digital backbone: IoT, AI and interoperability

To overcome the lack of environmental and mobility data, Cartagena deployed a citywide network of IoT sensors monitoring air quality, noise, temperature, humidity, and pedestrian flows. These sensors feed into an AI-enabled model that predicts emissions scenarios in real time.

All data streams are integrated via FIWARE, the open-source platform that ensures interoperability with other EU Smart City systems. The result: real-time dashboards, predictive tools, and simulations that support evidence-based urban management.

envair360: simulation for smarter decision-making

At the heart of this digital infrastructure lies envair360, a software platform that enables city officials to simulate the effects of various LEZ configurations before implementation. Users

can apply up to three types of restrictions at once, from vehicle type and speed limits to time-bound access for deliveries.

This level of granular control empowers decision-makers to explore tailored configurations for each neighbourhood or street, simulate pollution reduction outcomes, and communicate findings to citizens with confidence.

At the same time, heatmaps generated by envair360 offer a highly visual representation of the simulated impact, allowing policymakers to identify pollution hotspots, heat islands, and critical environmental thresholds. City officials can manually select zones on the map, which adds flexibility to the tool and lets them instantly evaluate different combinations of restrictions.

Additionally, the Prediction Service continuously evaluates the measures after implementation. It tracks the real-time impact of the chosen LEZ scenario, delivers emissions reduction data, and supports ongoing policy adjustments when needed

Citizen-centric by design

Technology in Cartagena is not used to control but to empower. The digital tools deployed are explicitly designed to put citizens at the centre. Rather than opting for an all-out ban of polluting vehicles, Cartagena used digital modelling to design a “superblock”: an urban area where access is carefully regulated but still allows for flexibility. It prioritises electric vehicles, bikes, pedestrians, and public transport, while reducing unnecessary car traffic.

The emphasis on minimising disruption was deliberate. The city intentionally avoided sweeping bans in favour of an adaptive model grounded in open data and public feedback. Restrictions were shaped not by ideology but by real-world behaviour and community priorities.

Insights that challenge assumptions

One of the most important findings from Cartagena’s data-driven approach was that climate, not traffic, was often the dominant factor behind poor air quality. While traffic did contribute by resuspending dust, many pollution peaks corresponded more closely with environmental conditions than with congestion.

This insight allowed the city to reframe its LEZ policies, targeting actual sources of emissions instead of perceived ones, resulting in more precise and fairer regulations, as well as improved public trust.

A scalable model for smart and sustainable cities

Cartagena’s Low Emission Zone is more than a compliance strategy, but a practical example of how local governments can use digital tools to make better, faster, and more inclusive decisions. For policymakers looking to balance sustainability goals with the realities of daily urban life, Cartagena shows how smart technology can be a powerful enabler, not just a technical add-on.

By combining sensor networks, AI, and simulation software, the city created a system that helps planners test policies before implementation, understand their likely impact, and adjust strategies based on real-time data.

Tools like envair360 allow local teams to model different traffic, access, and environmental regulations, and visualize how they would affect air quality and mobility. This means cities can move beyond guesswork and make evidence-based decisions, even with limited resources.

Cartagena’s use of open-source platforms like FIWARE also ensures that the system is interoperable and adaptable. Other cities can build on it, scale it up or down, and tailor it to their local context. Whether it’s identifying pollution hotspots, managing traffic during peak hours, or designing people-friendly zones, the platform gives city staff the flexibility and control to act with precision.

What makes this model truly replicable is its emphasis on continuous improvement. Through real-time monitoring and citizen engagement, Cartagena has created a feedback loop where data guides policy, and policy adapts to results. This approach helps build public trust and makes environmental action feel relevant and responsive, not imposed.

For cities aiming to modernise urban planning and meet climate targets without disrupting daily life, Cartagena’s experience offers a clear path: start with data, empower decision-makers with the right tools, and keep people at the centre of the process.