Waste disposal site or landfill

Public spaces in Colombo are disappearing due to rising land prices, causing infrastructure issues that harm citizens' health, especially in low-income areas (3). One proposed solution to address the problems caused by rapid urbanization is the creation of community gardens, which can at least improve low-income residents' diets and immune systems and address malnutrition (3).
Considering the limited urban space for both citizens and other living beings, the organization Eco-friendly Volunteers decided to create a community garden. The Metta Garden in Colombo (1, 2) aims to bring back urban biodiversity through organic home gardening, generating healthy food for people and creating living space for many other animals and plants (2). Following the Buddhist concept of Metta (loving-kindness to all beings), it promotes walking meditation paths and facilities to experience nature using all five sensory organs (1), in addition to being a place for experiencing loving-kindness for both human and non-human living beings, seen and unseen (4, 5).
It has become a training institute for many stakeholders seeking to grow organic food and earn a better income through the high demand for organic products (2). At the same time, it serves as a biodiversity spot, attracting butterflies, bees, and other forms of wildlife to an urban environment (2).
The area is located in the middle of a semi-urbanized area, on the outskirts of Boralesgamuwa (2, 3). Maintained by a group of volunteers, it features a greenhouse and a plot of land of around 5,000 sq feet, populated with vegetable patches, a butterfly garden, flowers and rare medicinal plants (3, 4). The garden was divided into four sections representing the Buddhist elements: water, heat, air, and solid. Each section features specific plants and designs, like a pond for water, a compost pit for heat, tall plants for air, and a rock garden for solid. The layout follows a mandala design based on permaculture principles (4).

The Thalangama wetlands are part of a network of wetland ecosystems around Colombo city that spread over 20 km2 and provide critical life support to the city. These ecosystems keep people safe from floods, cool the air, filter polluted water, provide food and medicines, and fight climate change (10). These wetlands have become an environmental protection area and a biodiversity hotspot in a rapidly urbanising environment, as they host an array of plants and animals, including the endangered fishing cat and otter (5, 10). In 2007, Thalangama Lake and its surroundings were declared an Environmental Protection Area (EPA) under the National Environmental Act (4, 5). This protected area covers approximately 118 hectares (4) and includes two man-made reservoirs: Thalangama Tank (11 ha) and Averihena Tank (3.2 ha), located just 300 meters apart (5). The area hosts floating and rooted plants, scrublands, and trees that provide habitat to up to 100 species of migratory, resident, and endemic birds throughout the year. In addition, the area supports 30 species of dragonflies, 12 species of reptiles, 10 species of mammals, and 15 species of freshwater fish (1, 4). Since the lakes and their surroundings were declared an EPA, only limited uses are permitted, such as traditional fishing and rice cultivation (4, 5). The lakes are also important for floodwater retention and have high scenic and aesthetic value, attracting many visitors, and scientific and educational activities (5, 13).
However, due to the area's rapid urbanisation, land values have increased significantly, leading to excessive landfilling and the reclamation of paddy lands for housing. This is compounded by the indiscriminate disposal of garbage and construction waste and the spread of invasive species (5). These challenges have also led to the engagement of surrounding communities in managing and maintaining it (11).

The environmental impact of golf has led to growing calls to make the sport more sustainable (1). Golf course maintenance often involves carbon-intensive fertilizers, frequent mowing, and, in some cases, the clearing of forests or trees that naturally absorb carbon dioxide to make room for expansive fairways (1). However, the Tournament Players Club (TPC) Michigan is working to create courses that benefit both golfers and the environment (2).
Fifteen years ago, the site was a neglected floodplain along the Rouge River, initially purchased by Henry Ford in 1915 and once littered with community waste and old motor parts from the Ford Motor Company (2-3). Today, it has been transformed into an 85.8-hectare course that supports a diverse range of wildlife, including birds, fish, foxes, and coyotes (2). Led by Jack Nicklaus, the restoration aimed to turn this former waste site into an eco-friendly course (2). With guidance from Audubon International, the course was converted into a wildlife sanctuary, becoming the world’s first golf course to receive the prestigious John James Audubon Environmental Steward Award for ecological restoration (2).
TPC Michigan features native Michigan plants, such as viburnums, which produce berries for wildlife, along with various native grasses (2). To prioritize environmental stewardship, the course managers have created buffer zones to protect natural habitats and conserve water by using coring methods to monitor soil moisture (2). Pesticide use is minimized; instead, staff monitor for signs of disease or pests and test the soil to determine the specific nutrients needed for the turf (2). The course’s links-style layout includes rolling fairways, tiered greens, and natural wetlands, with tee options ranging from 5.5 to 6.4 meters (4). By establishing a wildlife sanctuary, TPC Michigan offers golfers a unique experience that fosters a connection with nature (3).

The urban garden in Miraflores park (Huertas las Moreras) was established already in 1991 on an old waste dump and contains 10500 m2 of plots for locals to grow fruits and vegetables [Ref. 1]. The creation of the gardens was initiated by citizens who formed an association and implemented it in cooperation with the City of Seville. The citizens were discontent with the lack of green space in the area, and the urban gardens came to be alongside Miraflores Park, which was also pushed by the locals. The initial goals of the gardens were to allow locals to produce their own food and to host educational activities [Ref. 2]. More recent developments exemplify the focus on education and knowledge. In 2022, the citizen science project "Planta Bienstar" was carried out in the gardens, where high school students measured the lead levels in the soil and crops. The project aimed to investigate if lead levels posed a health risk and if the gardens could reduce levels over time. The project was organised by the non-profit Descubre Foundation and funded by the foundation and the regional Government of Andalusia. The project relied on the knowledge and efforts of the citizens, the students and gardeners in an intergenerational collaboration where the young could learn methods from their elders [Ref. 3, 4].

In 2022 an afforestation initiative was implemented near a landfill located in the Tutora commune (1 - 6). Organized by the City Hall of Tutora, the event brought together representatives from the regional government of Iasi County, the "Asociația de Dezvoltare Intercomunitară pentru Salubritate" (ADIS), and volunteers from SC Girexim SA, SC Salubris Iasi, and Edil Industri Iasi. Together, they planted 2,000 acacia saplings, donated by the Forestry Directorate of Iasi (6). The afforestation action took place under the umbrella of the regional environmental campaign "Iasi Mai Verde" (Iasi More Green), led by the County Council of Iasi. This campaign promotes a range of eco-friendly activities, including educational programs in schools, waste cleanup events, and afforestation initiatives in partnership with ADIS, while actively encouraging the support and participation of local municipalities from across the region (1, 3, & 7).
"Iasi Mai Verde" aligns with national environmental strategies such as the Ministry of the Environment's "Curățăm România" (Let's Clean Romania) and the annual Planting Forest Month (3 & 6).
On the same day, as part of the Iasi Mai Verde initiative, students from a local school in Tutora were given a practical education workshop on how waste management operates at the regional level. The students were also invited to witness the afforestation action and participate, fostering a deeper understanding of environmental stewardship (1- 5).
The newly planted trees are acting as a natural barrier, and help improve air quality by filtering dust, pollution, and waste particles originating from the nearby Tutora landfill. In turn, this contributes to better living conditions for the residents in close proximity to the landfill, enhancing both their health and overall quality of life (5).

The Kikås dump is a landfill in Mölndal, south of Gothenburg, where an area has been permanently covered with a sealing layer and inert material. This project aimed to utilise the area to increase biodiversity by establishing flowering meadows and an insect hotel, creating a habitat for wild bees, butterflies and birds [Ref. 1-3]. The City of Mölndal initated the project and sowed meadow flowers, established sand beds for burrowing insects, an uneven, rocky terrain and a large insect hotel [Ref. 1, 3]. The area is also meant to be a destination for recreation and learning about biodiversity. The Insect Hotel is marketed as the largest in Sweden, and it includes information signs and an outdoor classroom. The project is meant to raise awareness about biodiversity and ecosystem services such as pollination [Ref. 1, 4-6]. The area borders natural areas such as forests and wetlands and is meant to have positive ecological effects in the border zones. The project will contribute to the environmental goals of the city, in particular, "a rich plant and animal life" [Ref. 3]

The Fairy Garden, also known as the WOW Recreational Park, is a distinctive green space located near Diósgyőr Castle in Miskolc, Hungary. Since its opening in April 2020, the park has quickly gained popularity, earning third place in the 2020 Tourism Attraction of the Year award in the professional category. Once a neglected and polluted site with historical significance, the area was transformed by a local entrepreneur. After removing over sixty containers of waste, including hazardous materials, a park was created that harmonizes with the natural environment, preserving existing willow trees and integrating water features fed by local streams. When creating the park, the creators respected the plants of the area to the maximum, not a single tree was cut down, and the fruit trees were also kept.
The park boasts various decorative elements, including a carousel, a garden cinema, and other amenities. However, in September 2021, it was closed indefinitely for renovations. Gábor Vaszil, the lessee who had rented the land from the Miskolc municipality, intended to purchase the property for further development. Despite initial support from the local government, the transaction was halted due to concerns raised by the regional Water Management and Protection Authority regarding the protection of Miskolc's drinking water resources. Their ongoing investigation has delayed any further decisions about the sale or the future of the park. In the meantime, the garden remains open to the public for leisurely walks, similar to other municipal parks in Miskolc.
(Ref.1-4)

The initiative consists of an afforestation campaign promoted by the local government of La Paz, with the objective of planting 10,000 trees and shrubs (1 & 2). Carried out between 2023 and 2024, the campaign included plantations across all the macrodistricts of La Paz (1). To ensure the campaign's success, the municipality encouraged the participation of volunteers from various institutions, such as public services, environmental groups, schools and universities, neighborhood associations, church groups, and even Army and Navy units (1 & 2). The trees play specific roles in mitigating climate change, improving air quality, reducing odors from nearby landfills, and decreasing the risk of landslides and soil erosion (3 & 4). Furthermore, the campaign aims to foster environmental awareness among citizens and replace trees lost due to illegal deforestation (1).

The species selected for planting were provided by EMAVERDE, the public company responsible for managing green spaces in the city. The selection included primarily native species, along with a few introduced ones, all chosen for their resilience to La Paz's varying climate conditions (1, 2 & 4). Given the challenging climate and difficult soil conditions, the municipality informed volunteers about the importance of maintaining the saplings, particularly during drought periods, to ensure their proper growth (1 & 2). The campaign also supported the municipality’s urban development plan (Plan Territorial de Desarrollo Integral "Para Vivir Bien") and the "Plan Integral de Recuperación de la Tormenta a la Esperanza," the latter developed in response to extreme rain events and floods that occurred during the campaign months (5).

The increasing volume of solid waste, driven by Nairobi's growing population, has become one of the city's major challenges (Ref 1, 2). To address this issue and promote better environmental practices, authorities plan to convert all reclaimed illegal dumpsites into recreational and green spaces. The transformation of the former Kangemi Cemetery, abandoned for over 20 years and used as an illegal dumpsite, was the first initiative in this effort.
Led by Nairobi's Governor, H.E. Mike Sonko, and supported by the City County, the project was completed in 2018 and serves as a key example of these transformative measures (Ref 1, 2, 3). Previously, Kangemi Cemetery contained over 500 loads of illegal waste, but following a successful clean-up, it has been rehabilitated into a children's playground with recreational area, now named Kangemi Cemetery Memorial Park (Ref 3).

This initiative was launched by the local government of La Paz, focusing on afforestation of the Mallasa landfill, which was closed in 2004 (1-4 & 6-10). While some plantations were established in the area when the landfill was closed, the overall plan aimed to manage the waste until the site was sufficiently clean for new projects—a process expected to take at least a decade (6). By 2021, signs of biodiversity, including flora and fauna, had begun to return to the former landfill. In response, the municipality of La Paz implemented a project to plant 6,000 native tree species, along with other shrub species, to further enhance biodiversity regeneration and establish a second urban forest in the city (3 & 4 & 7 & 8).

The afforestation efforts took place between 2021 and 2022, coordinated through "forestry brigades" made up of diverse volunteer groups. These groups included members from public institutions, private company representatives, NGOs (both environmental and non-environmental), universities, religious organizations, and local citizen groups (8-10). A total of 12 hectares were reforested out of the 33-hectare area (1 & 7). Following this, the area was closed to the public and is expected to become a biodiversity sanctuary within ten years, with ongoing monitoring by the municipal environmental agency (7). Among the trees planted, some were chosen to attract birds with their fruit, others to support the pollination of hummingbirds and bees, while others were intended to enrich the soil with nutrients—all species being native to the region (3 & 7).

Additional goals of the initiative include raising awareness about climate change, fostering a sense of environmental stewardship through community engagement, and advancing the municipality's decarbonization plans (3 & 9). Some of the seedlings and saplings were purchased by the municipality at a cost of 6,160 euros, with private companies also contributing financial support to the initiative (1 & 7).