Green space is an overarching concept that includes all vegetated and aquatic areas, such as parks, gardens, playgrounds, sports fields, forests, allotments, and other natural areas. It also includes green corridors, vegetated pathways, and unpaved surfaces, which promote improved connectivity within the city. Urban green spaces play a crucial role in maintaining the balance between carbon and oxygen, enhancing air quality, reducing ozone levels, and contributing to the long-term sustainability of ecosystems and biodiversity.
Green spaces reflect the core principles of sustainable development while providing numerous benefits across economic, social, and environmental dimensions. From an economic perspective, urban green spaces increase property values, attract investment, and stimulate tourism. The value of vacant land, open areas, and surrounding residential and commercial properties can be significantly increased due to well-designed green spaces. From a social perspective, green spaces help promote improved mental and physical well-being by reducing stress, encouraging physical activity, and reducing obesity levels. They further promote recreation, cultural activities, social interaction, and engagement with the community. In fact, studies suggest that individuals residing within 1,600 meters of a green space are less likely to suffer from loneliness, particularly those who live alone. From an environmental perspective, green spaces are essential in the conservation of biodiversity by creating wildlife corridors, improving landscape quality, and enhancing aesthetic appeal.
Among Asian megacities, the proportion of green space in Dhaka is one of the lowest. The capital of Bangladesh, Dhaka, is also among the most densely populated and polluted cities in the world. Despite the many challenges of urban life, people continue to migrate to Dhaka in search of better opportunities. Improved living standards and employment opportunities are two of the major reasons that have increased population pressure. The combination of these factors has significantly contributed to the gradual decline of green spaces. The rapid loss of green space in Dhaka is now giving rise to serious environmental, social, and economic concerns. Therefore, the key question is how much green space a city needs to enhance human well-being, environmental quality, and sustainability.
According to the United Nations Environment Programme (UNEP), an ideal city should contain 25% green space, whereas Dhaka has only 8%. Rapid and unplanned urban growth, encroachment on parks and wetlands, weak regulatory enforcement, and related factors have all contributed to the alarming reduction of urban greenery. Over the years, natural landscapes have been progressively transformed into residential, transportation, and commercial developments, leaving minimal space for trees and open areas. Geospatial analyses highlight a significant long-term decline in green space. Research reveals that in Dhaka South City Corporation (DSCC), green space accounted for more than 46% of the area in 1991 but declined to 21.3% in 2001, 19.7% in 2011, and approximately 9.5% by 2021. Dense vegetationsuch as parks and tree-rich green areas currently stands at just 8% in DSCC. Research further shows that green space is unevenly distributed, with nearly 65% of dense vegetation concentrated in the northeastern part of the city. Consequently, most wards have less than 10% green space, and 17 wards have none at all. This uneven and shrinking distribution of green space has intensified urban problems such as rising temperatures, degradation of air quality, loss of biodiversity, and increasing inequality in access to public open spaces. Dhaka North City Corporation (DNCC) has also experienced a similar pattern, with substantial losses in green space from 1992 to 2022.
Over the past two decades, Dhaka has increasingly become an urban heat island, as the disappearance of green spaces has intensified this phenomenon, resulting in warmer and less pleasant living conditions, economic losses, and health risks for urban residents. A World Bank report (2024) states that extreme heat led to the loss of approximately 250 million workdays, with an estimated economic cost of up to US$1.78 billion, equivalent to around 0.4% of Bangladesh's GDP in 2024. Enhancing and maintaining urban parks and gardens would therefore be among the most effective strategies for mitigating the impacts of heat waves and heat exposure.
In Dhaka, brick kilns, industries, and construction sites are among the leading sources of air pollution, releasing large amounts of emissions, dust, and particulate matter into the atmosphere. Pollution is also generated by open waste burning and the use of heavy machinery. The burning of chemical waste further contributes to air pollution and poses serious public health risks. These significant negative externalities from industries, brick kilns, and construction sites are adversely affecting the remaining green spaces of Dhaka city, leading to biological stress on vegetation. To protect urban green spaces and address these negative externalities, an adequate amount of green space is essential for improving public health and ensuring overall environmental sustainability. Therefore, expanding urban green spaces can play a vital role in absorbing carbon emissions as well as PM2.5, PM10, etc.
Considering the issues discussed above, and in order to make Dhaka a resilient and sustainable city, there is a dire need to increase urban greening activities such as roadside tree planting, green roofs, the expansion of public parks, vertical gardens, and green buffer zones in industrial areas. These initiatives help increase vegetation cover and reduce air pollution in high-emission areas. Their effectiveness can be enhanced through collaboration among government and non-government agencies, organizations, academic institutions, and community groups.
Additionally, NGOs and academic institutions can contribute through research, advocacy for sustainable practices, and the development of public awareness and educational programs. Moreover, Bangladesh needs to increase per capita green space, as the Department of Environment (DoE) has reported that the availability of green space per person in Dhaka is significantly below the standard of World Health Organization (WHO).
Furthermore, the government can take initiatives from international case studies by adopting innovative ideas, policies, and best practices.Increasing proportion or required amount of green space in Dhaka will help to mitigate air pollution, heat exposure and excessive use of energy and water. It is important to keep in mind that natural environment is one of the pillars of sustainable development and achieving sustainable economic development and improved public health will be challenging at the expense of natural resources.
Dr Wasim Akram, Assistant Professor, Department of Economics, Southeast University, Sanzida Khan and Miskatun Rahman, Students, Department of Economics, Southeast University
