Dhaka's greatest crisis is not just pollution or falling water tables, but a rapid loss of biodiversity that threatens the city's capacity to support life. Reversing this decline must be the city's most urgent priority if it is to secure a liveable future for its people.
The Prime Minister's 12-point plan for a clean and green city is a good start. However, real recovery means changing past policies and making biodiversity central to every future decision.
Since 1990, Dhaka has lost more than 70 per cent of its wetlands to unplanned development. This loss has left the city more vulnerable to floods and extreme heat. In 2000, the Detailed Area Plan made things worse by rezoning much of this land, removing important natural protection. Rivers became dumping grounds, trees were cut down and floodplains disappeared beneath new buildings. These choices have added up, leaving the city dangerously exposed to disaster.
Restoring Dhaka's biodiversity is not just important-it is the foundation for the city's survival. Every urban decision, from infrastructure to management, must first prioritise water and green spaces to revive nature and secure the future.
Dhaka was once built around water and green spaces. The Buriganga, Turag, Balu and Shitalakkhya rivers helped control temperature and flooding. Wetlands, canals and trees soaked up monsoon rains and kept the city cool. Biodiversity was a key part of the city's infrastructure.
Now, even regular rainfall can cause floods in Dhaka, and heatwaves can be deadly. Filling wetlands, blocking canals and cutting down trees have made the city hotter and weaker. Air-conditioned buildings add to the heat. Fireflies, frogs and common birds like crows have almost vanished, though thousands of Black Kites remain.
Biodiversity loss threatens the environment, economy and public health. Recovery requires active community involvement and must guide city planning beyond surface-level solutions like tree planting or cleanliness drives.
First, we must protect wetlands as vital ecological resources andupdate the Detailed Area Plan to ensure the retention of ponds and floodplains. Once lost, ecosystems cannot be fully restored. Prevention is more effective and affordable than artificial drainage.
Second, we must enforce waste and land use rules to revive rivers. The government must make river restoration a top priority.
Third, urban forestry must do more than beautify. Unplanned tree planting, poor soil prep and lack of care are ineffective. Dhaka needs native trees, green corridors and tree-coverage requirements for new buildings. Biodiversity must be connected, rather than remain scattered.
Fourth, we need robust environmental impact reviews for every project. If mature trees are removed during road expansion or construction, developers must implement a detailed, time-bound compensatory plan. Any loss of permeable surface should be offset by funded restoration elsewhere. Economic decisions must fully account for environmental costs.
Finally, Dhaka needs a single strong ecological coordination unit with real authority to enforce rules. Right now, responsibilities are split among the city corporations, RAJUK, WASA and other ministries, leading to scattered efforts. This new unit should integrate planning, drainage, housing and transport into a single environmental plan to effectively protect biodiversity.
Some argue that a crowded city like Dhaka cannot focus on biodiversity. In reality, ignoring it results in higher energy and health costs, lower productivity and worse pollution. According to a World Bank report, Bangladesh lost USD 1.78 billion in 2024 due to heat-related health problems and reduced productivity, equivalent to 0.4% of GDP, as rising temperatures trigger widespread physical and mental health issues. Losing biodiversity compounds these problems.
There is also a social justice aspect to this issue. Environmental damage does not affect everyone equally. People in informal settlements suffer most during floods, and low-income communities have less access to green spaces. When wetlands disappear, people experiencing poverty often lose both their livelihoods and their protection.
Restoring biodiversity does not mean stopping urban growth. It means redesigning the city. Cities around the world are bringing back rivers, reopening old canals and growing urban forests-not just for looks, but to become stronger. Dhaka can learn from these examples and adapt them to its own needs.
Every filled wetland, polluted canal or lost mature tree raises Dhaka's risk of disaster. The longer we wait, the higher the cost of doing nothing. We often talk about GDP growth, big projects and changing skylines as signs of progress. But a city's real strength is found under the concrete: in soil that soaks up water, wetlands that protect against storms, trees that cool neighbourhoods and rivers that flow freely.
The city lost its biodiversity because of specific policies. The only way to reverse this crisis is to make every future policy and decision explicitly protect and restore nature's role in the city.
Dhaka's future depends on regaining its biodiversity. This requires direct action from everyone: advocating for and enforcing strong policies, participating in local restoration and holding leaders accountable at every level.
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