Dhaka, the capital of Bangladesh, is one of the fastest-growing megacities in the world. With its rapid urbanization, population explosion, and industrial expansion, the city has seen massive infrastructural changes over the past few decades. However, this growth has come at a steep cost: Dhaka is consistently ranked among the most air-polluted cities globally. The problem has reached alarming levels, posing serious threats to public health, the environment, and the overall livability of the city. But what are the reasons behind such severe air pollution in Dhaka?
1. Unplanned Urbanization
One of the most significant contributors to Dhaka’s air pollution is unplanned and unregulated urbanization. The city’s infrastructure has not been able to keep up with the rising population. Buildings are constructed without proper environmental assessments. Roads are often narrow and congested, leaving no space for trees or green areas that could act as natural air filters. The uncontrolled expansion of the city results in dust and construction debris becoming a constant presence in the air.
2. Brick Kilns
A major source of air pollution in Dhaka is the thousands of brick kilns operating around the city’s outskirts. These kilns burn low-grade coal, wood, and even used tires, which release large amounts of particulate matter (PM2.5 and PM10), carbon monoxide, sulfur dioxide, and other toxic gases. According to studies, brick kilns are responsible for a significant portion of the city's winter smog, when pollution levels peak due to stagnant air and temperature inversion.
3. Vehicular Emissions
Dhaka’s streets are choked with a variety of vehicles, many of which are outdated and poorly maintained. These include buses, trucks, and three-wheelers that run on diesel and emit black smoke. Traffic congestion causes vehicles to spend more time idling, leading to higher fuel consumption and greater emission of pollutants such as nitrogen oxides and particulate matter. Furthermore, the lack of a strong vehicle emission control policy makes this problem worse.
4. Construction Dust
With new buildings, roads, and flyovers being constructed continuously, dust has become a part of daily life in Dhaka. Construction sites are often left uncovered, and materials like sand and cement are transported without proper safety measures. The fine dust particles become airborne and linger in the atmosphere, significantly degrading air quality. During the dry season, this dust mixes with industrial and vehicular emissions, creating a toxic cloud over the city.
5. Industrial Pollution
Many of Dhaka’s industries operate in residential or semi-residential areas and release untreated emissions into the air. Textile dyeing factories, tanneries, steel re-rolling mills, and plastic manufacturing units contribute to the emission of volatile organic compounds (VOCs), heavy metals, and acidic gases. Most of these industries lack proper air filtration systems, and environmental regulations are either weak or poorly enforced.
6. Lack of Green Spaces
Green areas in Dhaka are rapidly disappearing due to the demand for housing and commercial infrastructure. Trees and parks not only offer a respite from urban heat but also play a crucial role in filtering air pollutants. The scarcity of green coverage means there is less natural cleansing of the air, which contributes to the persistence of pollutants in the atmosphere.
7. Climate and Geography
Dhaka’s geography and climate also play a role in trapping polluted air. The city is located in a low-lying floodplain, and during the winter months, temperature inversions trap cool air close to the ground. This prevents pollutants from dispersing into the upper atmosphere, causing the air near the ground to become highly contaminated. Additionally, the monsoon season temporarily reduces pollution levels, but the relief is short-lived.
8. Poor Waste Management and Open Burning
Open burning of household waste, plastic, and medical refuse is a common sight in Dhaka. This practice releases a cocktail of harmful pollutants, including dioxins and furans, which are extremely toxic and carcinogenic. The lack of a structured waste disposal system and low public awareness about the dangers of open burning contribute to the worsening of air quality.
9. Policy Gaps and Weak Enforcement
Bangladesh has environmental laws and policies on paper, such as the Environment Conservation Act and regulations on air quality standards. However, enforcement is often lax due to corruption, lack of coordination between government bodies, and resource limitations. Environmental Impact Assessments (EIA) are either skipped or manipulated to favor development. As a result, polluters often go unpunished, and air quality continues to deteriorate.
10. Public Awareness and Behavior
Public awareness regarding the health impacts of air pollution remains relatively low. People often do not use masks or air purifiers, and there is limited civic pressure on authorities to act. Sustainable practices such as carpooling, using public transportation, or planting trees are not widely promoted or practiced. A cultural shift toward environmental responsibility is urgently needed.
The consequences of air pollution in Dhaka are grave. According to various health studies, exposure to high levels of air pollution can cause or worsen respiratory diseases like asthma, bronchitis, and COPD. It also increases the risk of heart disease, stroke, and lung cancer. Children, the elderly, and people with pre-existing conditions are particularly vulnerable. The World Bank has estimated that air pollution costs Bangladesh billions of dollars annually in health care and lost productivity.
Conclusion
Dhaka’s air pollution crisis is a complex and multi-faceted issue rooted in rapid, unregulated development and weak governance. To address it, a coordinated effort is needed involving stricter regulation of industries and brick kilns, improved public transport, investment in green infrastructure, and stronger enforcement of environmental laws. Public awareness campaigns and civic engagement must also play a vital role. Without urgent and sustained action, Dhaka risks becoming increasingly uninhabitable for its millions of residents.
Content Writer: Musabbir Uddin Shovon
Poster Designer: সুমাইয়া ইসলাম
