Regulation of built environment

The green belt regeneration project along the Byzantine Walls of Thessaloniki aims to revitalize the neglected green spaces surrounding these historic fortifications, which span 4 kilometers and are recognized as a UNESCO World Heritage site for their remarkable Byzantine architecture. The walls are located in Thessaloniki’s densely populated Upper Town, a factor that contributed to their environmental degradation. As such, the project focuses on restoring the degraded space surrounding the walls, improving the urban microclimate, and strengthening urban resilience while maintaining the area’s traditional character. By integrating heritage conservation with sustainable green infrastructure, the initiative seeks to provide both environmental and social benefits to the local community. Proposed by the Municipality of Thessaloniki and approved by the Greek government as part of a program that focuses on Central Macedonia, the project envisions a revitalized green zone along the walls, with vegetation and different types of trees being planted. However, some local families have expressed concerns, as the project involved the demolition of certain homes in the officially designated green belt area. (Refs. 1, 2, 3, 4, 14).

The "Plan Arbre" is a tool for ecological planning and renaturation aiming to plant 308,000 trees between 2023 and 2029, sourced from the municipal nursery with seeds purchased from local suppliers (Ref 1, Ref 2). In 2023, 14,922 trees were planted, with plans to double this number in 2024 (Ref 1). The project addresses the loss of 50% of Marseille's natural spaces over the past 75 years, aiming to reverse this trend and reintroduce nature into the urban environment (Ref 2). It also tackles issues like drought and heatwaves, particularly in summer, by using trees and shrubs to cool the air, restore biodiversity, reduce air pollution, and enhance public spaces while absorbing CO2 (Ref 2).

The plan is divided into two phases. Phase I focuses on planting in Marseille's 58 parks and 273 squares and gardens, as well as around childcare centres, schools, socio-cultural centres, and sports facilities (Ref 2, Ref 3). From 2020 to 2023, various improvements were made, including playground renovations, installation of misting systems, automatic watering, and the creation of a CrossFit area (Ref 3). Phase II will involve identifying major boulevards, avenues, and streets lacking trees to enhance the urban canopy (Ref 2).
A diverse range of tree species were selected for their drought resistance, water efficiency, and ability to attract biodiversity (Ref 2, Ref 3). The project also focuses on increasing biodiversity and managing invasive species through natural methods to protect trees from pests without chemicals (Ref 3). Furthermore, the initiative includes de-impermeabilizing soils and implementing a smart irrigation system with tensiometric sensors, developed with the start-up GreenCityZen, which has saved 66% of water in two years (Ref 3). The Plan Arbre also promotes citizen participation, with 23 parks selected for community gardening projects, where ten winning associations will receive plants from the municipal nursery (Ref 1).

Since the 1980s, the Graefekiez neighborhood in Berlin's Friedrichshain-Kreuzberg district has been a traffic-calmed area where all road users are treated equally, driving is limited to walking speed, and cars are permitted to stop anywhere. However, this once-progressive concept no longer functions effectively due to the significant increase in cars and delivery vehicles over the years. The streets no longer resemble a traffic-calmed zone, with traditional layouts featuring roadways, sidewalks, and parking spaces. As a result, many users fail to recognize the traffic-calmed nature of the area, leading to safety issues: vehicles drive too fast, delivery traffic causes conflicts, and streets are difficult to navigate safely.
Berlin’s transport sector faces the challenge of meeting legally mandated CO₂ reduction targets. Achieving these goals requires bold measures, including limiting private motorized transport (MIV), especially in densely populated areas where residents and visitors have access to alternative modes of transportation.
The "Graefekiez" project addresses these challenges through urban redevelopment aimed at improving livability and promoting sustainable urban mobility. Car parking has been banned from the streets, freeing up space for communal use such as lounge areas. As part of the "Graefekiez" project, the district office is converting parking spaces into green spaces and expanding tree disks to adapt to the climate and promote a sponge city.
The project was developed collaboratively with residents and NGOs through a participatory process led by the Friedrichshain-Kreuzberg district office, in partnership with the Berlin Social Science Center and Paper Planes e.V. Implementation began in 2023 on Graefestraße and Bockhstraße.After a six-month trial period, the district office decided in 2024 to make the measures permanent.
This initiative advances a safer, greener, inclusive urban environment while meeting climate and community goals. (Ref. 1, 2, 3)

The project, implemented by the municipality of Cagliari, involves the creation of a new garden in 2021 on Via Eroi d’Italia, in the Pirri municipality, located about 5 km from the center of Cagliari. This initiative is part of a broader effort to reclaim degraded urban green spaces. The garden spans approximately 900 square meters and was previously an unused lot serving as a parking area. Its transformation required substantial groundwork, including soil scarification and leveling, to prepare the area for its new purpose. The garden is now enclosed, with pedestrian access via two gates leading to a paved walkway.
Inside, the garden is divided into two main sections: a children's play area and a landscaped green space. The play area covers about 100 square meters and features durable artificial grass, swings, a spring toy, a universally accessible table, a children's table, benches, and a multi-compartment recycling bin. The green space, approximately 200 square meters, is planted with low-water-use grass and surrounded by drought-resistant plants like albizia, oleander, and lantana, chosen for their low water consumption and resilience to environmental stress. An underground irrigation system, linked to a 5,000-liter water tank, ensures efficient water use.
The remaining 600 sqm outside forms a parking area with 1 disabled space, 2 motorcycle spaces, 1 bicycle rack, and 15 car spaces.
The garden also incorporates sustainable elements, such as LED lighting for energy efficiency and a mural by renowned Sardinian artist Manu Invisible, depicting sunlit forest undergrowth in shades of green. This project responds to citizens' requests and prioritizes resource efficiency by reducing hazardous substances and minimizing waste. The materials used, including recycled plastics, and the selection of plants were chosen to match local ecological conditions, enhancing the garden's sustainability and reducing its environmental impact (Refs. 1, 2, 3, 4 & 5).

Parque Lácides Segovia is an urban park located on Isla de Manga in Cartagena, Colombia. The park was inaugurated and revitalizated in June 2014 to serve as a multifunctional green space promoting cultural, social, and environmental activities. Named after General Lácides Segovia, a notable figure in Cartagena's history, the park aimed to provide a family-friendly and culturally enriching environment (ref 1). The primary goal was to transform a neglected urban area into a dynamic public space that fosters community interaction and enhances local culture. The park aimed to create a safe, inclusive, and accessible environment for residents of all ages, promoting social integration and cultural activities. Additionally, the project sought to establish a green area contributing to the ecological health of the city through urban greenery (ref 1, 2).
The first revitalization in 2014 involved facilities, planting native trees, and setting up public amenities such as Wi-Fi, seating, and cultural spaces(1, 2, 3).
This new revitalization in 2024, led by the local government of Cartagena, will focus on enhancing the infrastructure of both the park and the surrounding sports area in Manga to improve sustainability. The project has an estimated budget of approximately USD 675,000. The improvement works to provide better facilities and infrastructure to support recreational and sports activities, benefiting the community and promoting a healthier urban environment (ref 6). The park is essential for the community; it was recently the subject of several citizen science projects led by the Montessori School, including research identifying the park's ecosystem services (ref 3).

The Köprüköy Mosque in Adana, commonly named "green mosque", is one of a kind in Türkiye (Ref. 2,5). Its building and minaret are almost entirely covered by poison ivy and appear in vivid green colour from afar. Founded in 1929, it had to be remodelled in the early 60s as it couldn't sufficiently accommodate worshippers in the growing district. The mosque was then entirely built and rebuilt by the community, with its maintenance overseen by the mosque's protection association (Ref. 4). In the 70s, the ivy was planted and has since helped to protect the building from environmental stressors and keep visitors inside the garden and mosque cool during the summer heat (Ref. 4,5,6) Furthermore, the mosque’s well-maintained garden, home to around 280 species, is adored by local, national, and international visitors and tourists, as well as the media (Ref. 1,3,7). Frequent maintenance and rotation of the garden's flowers keep its appearance and function intact, one of which is the profound impact on visitors’ well-being, with many praising the unique atmosphere of the mosque that evokes peace, comfort, and spirituality (Ref. 1,3,4).
During COVID-19, the mosque could only host worshippers during praying hours, after which it quickly continued to bring people back together to garden, rest and socialize throughout the day (Ref. 1).

A biodiversity park was built on an abandoned plot of land that felt unsafe to local residents. In the future, the plot may eventually be used for the construction of something more permanent. In the meantime, this project seeks to increase safety and access to greenspace while benefiting biodiversity, specifically flowers and insects.
Recycled materials were used to create the structure of the park, places to sit and insect hotels, while trees and a flowering meadow were planted. A mix of annual and perennial flowers was used to promote biodiversity over time. The locals are reported to be happy with the project. Familjebostäder i Göteborg AB, a publicly owned real estate company, conducted the project. [Ref. 1-5]

In 2022, the municipality of Cagliari launched a project to revitalize Viale Trieste, one of its avenues, by redesigning its roads and pedestrian areas and adding new green spaces. The project covers approximately 1,300 meters and 36,500 square meters, and will be completed in two phases, each focusing on different sections of the avenue. With a budget of 12 million euros, funded by municipal, national, and EU resources, the aim is to transform Viale Trieste into a vibrant, accessible, and attractive space for everyone.

The renewal will introduce new green spaces and improved drainage systems to enhance soil permeability. As part of this, some trees will be relocated to other areas of the city to address root issues and improve survival rates. Dead or unstable ficus trees will be removed, while 79 new trees will be planted. Older ficus trees will be relocated to city parks, with younger ones planted along the avenue to prevent pavement damage and promote sustainability. The project also includes upgrading water supply and drainage systems to manage stormwater more effectively, reducing the risk of flooding and improving sustainability. Public lighting will be modernized, with new street lamps and dedicated lighting for pedestrian and bicycle paths to make the area safer and more welcoming after dark.

However, the community has expressed concerns about the project, citing safety issues, delays, disruptions, and poor communication from officials. There is also significant opposition to replacing the historic ficus trees, valued for their environmental and historical significance, with Chinese pear trees and younger ficus (Refs. 1, 2, 3, 4, 5, 6, 11, 16).

In the city of Ciudad Juárez, the municipality, in collaboration with UN-Habitat, aims to design and create a park that encompasses the yards and unmaintained areas surrounding the railway station, transforming these spaces into an accessible and safe public area. This project covers over 500,000 square meters and addresses not only degraded areas but also several public squares. Described as "a coordinated urban recycling strategy," this initiative seeks to repurpose existing public squares and rehabilitate neglected spaces into vibrant green areas that feature universal accessibility, native vegetation, and urban furniture designed to enhance safety. The project also aims to provide increased recreational opportunities, improve permeability, and introduce additional shaded areas. A key component of improving permeability involves the restoration and incorporation of acequias—traditional historical irrigation systems that absorb and manage excess rainwater, thereby reducing the likelihood of flash floods.
Additionally, the project focuses on the restoration and promotion of significant historical buildings, such as the old railway station and the whiskey factory, integrating them into a larger cultural and sports facility area at the municipal scale. The overarching goal is to revitalize the site through effective coordination with the relevant authorities responsible for the spaces adjacent to the railway station, stretching from Plaza Misión de Guadalupe to Blvd. Municipio Libre. This collaborative effort aims to accommodate both sports and cultural facilities while also creating a green corridor.
Furthermore, the project intends to reforest, redesign, and enhance Plaza Misión de Guadalupe, Plaza Monumento a Benito Juárez, and other residual public spaces and gardens. This initiative aligns with its Public Space Strategy, which emphasizes the development of gender-inclusive and resilient public spaces.(Ref 1, 3, 4).

The Silk District is a real estate project by Prime Kapital in partnership with MAS P.L.C., integrating green spaces into its urban design (1-10). It focuses on regenerating a brownfield site, an abandoned industrial area left undeveloped in one of Iasi's neighborhoods (1). The project aims to revitalize the area, improving its aesthetics, reducing pollution, and repurposing it into a commercial and residential space (1). A key feature of the project is the incorporation of green spaces throughout its design (1).
The development spans 101,000 square meters, with 40,500 square meters (combined) dedicated to green spaces and "car-free" open areas (1, 2, 6, p.2). These green elements are designed to offer spaces for relaxation, recreation, and social interaction, while also contributing to environmental benefits such as air filtration, temperature regulation, rainwater drainage, and soil erosion prevention, all promoting better health for residents (1, 2, 4, 6, p.12). The landscape design includes “green islands” and vegetation-covered roofs for parking structures (4).
Launched in 2021 after receiving municipal approval, the project is ongoing and has already made significant progress, with over 10,000 perennial plants and 401 trees planted (4, 9). Upon completion, the landscape will feature 7,100 square meters of perennials, 3,000 square meters of shrubs, and an urban forest containing 2,400 trees (6, p.12).
The total investment in the project is €20,000,000 (7). In 2024, one of the completed office buildings earned a BREEAM green certification, achieving one of the highest possible scores, in collaboration with the consulting firm BuildGreen (5, 8). The landscape design was carried out by the architectural firm Beros Abdul+ (4). Before receiving approval, the project was opened for public consultation, and an independent online survey showed strong support from the community (15, 16).