B. Particular population groups have reported unequal distribution of project impacts or dissatisfaction.

Rapid urbanization and a population density of 6,247 people per km² have placed significant stress on Nairobi's natural resources (Ref 1). The 40-km long Nairobi River Basin, originating from the Ondiri Swamp, serves as a vital water source for the city (Ref 1, 2). However, it has suffered severe pollution from untreated sewage, solid waste, industrial contaminants, plastics, and agricultural runoff (Ref 1, 3). This degradation has had a serious impact on the ecosystem, local residents, and biodiversity (Ref 3).

To address these issues, the Nairobi River Basin Programme (NRBP), sponsored by UNEP, was launched in 1999 (Ref 4). Since then, government and non-state actors have worked together on solid waste management, riparian restoration, and wastewater control (Ref 1). The program was implemented in two phases: Phase I (2003–2006) and Phase II (2006–2009), involving stakeholders from the government, private sector, and civil society (Ref 1, 4, 5). Despite these efforts, a study from 2017 found significant tree removal along the river, and between 1988 and 2014, encroachment into the 30-meter riparian buffer zone dramatically increased, particularly between 2010 and 2014, further degrading the river’s health (Ref 1).

The Tirana Vertical Forest is part of the city's 2030 Master Plan and aims to enhance urban biodiversity and create green spaces through innovative urban design (Ref. 1,2). The project was developed by Stefano Boeri Architetti, the same studio that has designed similar, well-known structures in cities like Milan, Utrecht and Nanjing (Ref. 6). The completion of the 21-floor building is expected in late 2024 and will feature 105 apartments and a commercial ground floor as well as 145 trees and over 3,200 shrubs and bushes which are integrated into the balconies and façade of the project (Ref. 1,2,3). Various Mediterranean plants have been incorporated, including colourful, scented and aromatic types, which harmonize with the local ecosystem. To maximise the space available for green features, a dynamic structure with alternating balconies and full-height windows has been built (Ref. 1,2). Ultimately, the project anticipates improving air quality, reducing noise, and providing insulation. The greenery is expected to capture fine particulate matter and up to 8 tones of Co2 per year while also creating a healthier microclimate for those inside the building (Ref. 1,6).

The Adana Central Park stretches along both riverbanks of the Seyhan River. The idea was first introduced by the former mayor of the city, Aytaç Durak, in the late 80s to address the need for accessible green spaces in the developing area (Ref, 2). Previously, citrus gardens and informal settlements were located on these riverbanks, which now host over 400.000 plants and 67 different tree species on an area of 33 ha (Ref. 2,5,6). In 1998 construction of the park began, which lasted until 2004 (Ref. 2,5). The park is appreciated by visitors for its aesthetically landscaped appearance and the many amenities for children, youth, relaxation and socializing (Ref. 7). The two sides of the river are connected via bridges or, alternatively, visitors can board the Venetian style gondolas to access either side (Ref. 5). In 2021, park lighting infrastructure has been extensively replaced to ensure accessibility and safety during day and nighttime (Ref. 3).

In response to rising food prices and knowing that much of the country's agriculture depends on imported chemical fertilisers, the Municipality of La Molina has developed the Molihuertos programme to provide the residents of the district of La Molina with organic crops for their own consumption and to improve their food security (1, 3). As part of the programme, the municipality implemented municipal plots in different parks in the district. Eleven plots were installed in O'Higgins Park, where residents actively participate in the planting and subsequent harvesting of vegetables, aromatic and medicinal plants, which they consume by themselves (2, 3). Through the programme, the municipality trains and provides different varieties of vegetables and aromatic herbs to more than 800 currently enrolled residents (2). These gardens are managed under organic agriculture, which would help to mitigate a possible overpricing and/or shortage of vegetables in Lima, as they do not depend on chemical fertilisers such as urea, but on organic fertilisers such as compost and manure (3). In addition, residents can sign up to receive drawers with planted vegetables so that they can plant and harvest them at home, either for self-sufficiency or to sell if they wish to do so in the itinerant markets organised by the municipality (9).

The Miraflores Bicentennial Park has been built on the Malecón de la Reserva and the Quebrada de Armendáriz. It was inaugurated in June 2022 as one of the created projects within the framework of the commemorations of the 200 years of Independence celebrations (1). It is considered a new green lung of Lima (2), as it has a green area of 30,400 square metres and stands on one of the cliffs of the Costa Verde (1). It has a system of terraces that replicates the construction model of the Incas, which has made it possible to additionally reinforce the soil and the slopes with the use of retaining walls up to 10 metres high, with horizontal geogrids and vertical geocells (1, 2). It was structured on a stabilised slope in order to mitigate the risk of landslides (4), and an irrigation system was implemented to stabilise the soil (4).
This space was built as a biodiversity garden with more than 160,000 xerophilic coastal species with low water consumption, 300 trees and 80 palm trees. It also offers places for tourism, such as viewpoints and squares, where cultural events, open-air activities and rest areas are held (1). It also aims to connect aspects of landscape conservation, preservation of biodiversity in the city, and the construction of a cultural landscape in which human action is complementary and friendly to the natural environment (9). Finally, it seeks to contribute to the reduction of the municipality's carbon footprint by reducing the harmful effects of urban expansion on the Lima cliff ecosystem, such as deforestation, water pollution and loss of biodiversity (9).

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).

Historically, the area of San Paolo in Cagliari has suffered from environmental degradation and illegal dumping, making it an unsightly entrance to the city. In 2022, the Città Metropolitana di Cagliari, initiated a project to transform this degraded area into a urban park featuring 7,000 new plants, including olive trees, junipers, lentisks, myrtle, rosemary, tamarisks, and Aleppo pines. Managed by the municiplaity of Cagliari, and funded by a €500,000 grant from the Ministry of Ecological Transition, this initiative will cover 4.7 hectares between Via San Paolo and the Santa Gilla Lagoon, creating a natural corridor connecting the city to the lagoon. The project aims not only to restore the land but also to enhance both metropolitan and municipal environmental requalification plans.
A multidisciplinary team, including a forestry technician, agronomist, and biologist, developed the project to ensure it is environmentally sustainable and suited to the local ecosystem.
The work on the project began in June of 2022 with land preparation, removal of invasive species, and waste collection, resulting in the clearing of over 5 tons of rubbish. By December, around 3,000 plants had already been planted, with the remaining work, including the installation of an irrigation system, scheduled for completion by January 2023. The selected plant species are fast-growing, and within two years, the shrubs are expected to reach a height of about two meters. The park is planned to open to the public in 2024, providing a new green space for walking and outdoor activities.
The San Paolo urban park project has encountered obstacles, mainly due to the expropriation of buildings, leading to legal disputes, permit delays, and a temporary halt caused by a tender-related issue. The site is currently overgrown and unused, showing clear signs of neglect. (Refs. 1, 2, 3, 4 & 5).

The "Line Park" project in Belgrade aims to create a continuous green belt spanning 4.6 kilometres and covering over 48 hectares. As such, the project will revitalize the former railway corridor from "Beton Hala", just below the Belgrade Fortress, to the Pancevac Bridge. Inspired by notable urban parks like New York's "High Line", Moscow's "Zagrađe," and Toronto's "Rail Corridor," it will become a major recreational destination and also help to alleviate the pressures from the city's heavy air pollution and summer heat (Ref. 5, 6).
The park will be divided into ten thematic sections dedicated to aromatic plant and flower gardens, urban gardening and beekeeping, sports facilities, a newly built university campus and more. Additionally, there will be an amphitheatre and facilities for outdoor education. To further integrate green infrastructure, new buildings will have green roofs and walls (Ref. 2,5). Ultimately, the park integrates a number of amenities into the entire city.
The development of the park also introduced innovative co-creation mechanisms in terms of governance and planning. Since Belgrade is part of the multinational CLEVER Cities Initiative, the city's Secretariat for Environmental Protection suggested the use of the site as a pilot test for introducing nature-based solutions in urban planning and with diverse stakeholders' input. Several workshops, focus groups, and consultations took place between 2019 and 2021, which facilitated the diversity of ideas that have been adopted into the official construction plan (Ref. 1, 2). Despite these successes, civil society groups raise concerns over the extraordinary cost of 70 million euros, displacement of Roma communities and the interest of real estate developers that may undermine the project's original cause (Ref. 3, 8).

Named after the former Mexican president Lázaro Cárdenas, this green corridor project stretches over 4,5 km throughout one of the most densely populated areas in Belgrade. It was first built in the 1970s, connecting the building blocks 45, 44 and 70 of Novi Beograd, but has deteriorated since then (Ref. 4,9). Given the fact that close to 40.000 people live in the area which its highly vulnerable to climate change, action was taken to fully reconstruct the corridor for the benefit of local and surrounding residents (Ref. 3,4).
The project was implemented in three phases, according to the three blocks adjacent to the construction site starting in 2019. During the third implementation phase in 2022, however, major delays occurred due to disagreements with the local neighbourhood association "Common Action Block 70 and 70a", which demanded to be taken into consideration in the project's design (Ref. 2,5). Despite some cooperation between the responsible authority (Greenery Belgrade) and the association, demands could not be met (Ref. 5). In the end, the project was carried out as originally planned by the authorities, with a delay of approximately one year. Ultimately, the green corridor provides ample amenities for sports (bicycle lanes, basketball courts, playgrounds, etc.) and recreational activities (benches, chess area) as well as low-barrier infrastructure for all age groups (Ref. 9).
The project was initiated by President Aleksandar Vučić and supported by the current mayor of Belgrade, Šapić, who both have roots in the district (Ref. 4,6).

Barranco, the smallest district of Metropolitan Lima, is suffering from serious environmental problems that are affecting its inhabitants. Environmental degradation is a consequence of the increase in large buildings (real estate boom), which reduces green space areas and causes a deficit of vegetation in the district. Additionally, there are high levels of air pollution due to car traffic, which has been accentuated by the lack of green areas in the area, which affects the environmental quality and the population's quality of life (1).
Additionally, the district doesn't have more free public areas where new green areas can be created. Due to these combined pressures, the local government has looked for alternatives, considering private areas, which have a high potential to implement green roofs and vertical gardens, which can contribute to face Climate Change as a mitigation strategy and improve the quality of life (1). The Green Roofs and Green Walls strategy is proposed to build citizen culture, nature appreciation, landscape, and ecosystems (2, 3). The aim is, therefore, to encourage the inhabitants of the district to progressively install green roofs and walls, employing an economic incentive in the taxes paid to maintain public green areas (4).
The programme is oriented to generate environmental benefits such as the reduction of air pollution, acoustic insulation, thermal comfort, and increase of green areas (m2) per inhabitant, and social benefits such as the improvement of the living conditions and health of the inhabitants of the district (1, 3), the promotion of social relations (1), the aesthetic improvement of the city, and the possibility of producing food for self-consumption, as there is support in the implementation of hydroponic systems in the green walls and roofs (1, 3). Its implementation focuses on new, under construction or existing residential, commercial, office or lodging buildings (3).