Urban pollution is a pressing issue that affects cities worldwide, and Dhaka, the capital of Bangladesh, stands as a stark example of the challenges that densely populated urban areas face. This investigative research aims to delve into the causes and extent of urban pollution in Dhaka, shedding light on the multifaceted factors contributing to the city’s deteriorating air and environmental quality.

Urban pollution: Dhaka, Bangladesh - Sheet1
A canal in the Bangladesh capital, Dhaka _©www.rte.ie/

Rapid urbanization

Dhaka is one of the fastest-growing cities in the world. The city’s population has increased from 10 million in 2000 to over 20 million in 2023. This rapid urbanization has put a strain on the city’s infrastructure, including its ability to manage waste and traffic.

Built Environment Overload

Dhaka‘s built environment is under tremendous pressure, with the built-up ratio estimated at over 60%, as reported by the World Bank. This figure highlights that more than 60% of Dhaka’s land is covered by buildings and other structures, leaving very limited space for green areas. A mere 1% of the city’s land is allocated to parks and gardens, significantly below the World Health Organization’s (WHO) recommended standard of 9 square meters of green space per person. Such scarcity of green pockets exacerbates air pollution by trapping pollutants and hindering their dispersion.

Population Explosion

Dhaka is home to over 20 million people, making it one of the most densely populated cities globally. The high population density amplifies several factors contributing to air pollution. Firstly, the sheer number of people translates into more vehicles on the road, leading to increased emissions of pollutants from transportation. Secondly, the city’s growing population generates more waste, which, when improperly managed, can further pollute the air.

Predictably, Dhaka’s population continues to expand rapidly, with an estimated 25 million residents expected by 2025. This exponential growth places additional stress on the city’s infrastructure, which, when coupled with an inadequate waste management system, will likely worsen air pollution.

Urban pollution: Dhaka, Bangladesh - Sheet2
Vehicular Traffic  in Dhaka _©Suvra Kanti Das

Vehicular Traffic 

Vehicular traffic is a major source of air pollution in Dhaka. It is the largest source of air pollution, accounting for about 60% of the total emissions. With over 4 million registered vehicles and the number steadily rising, the city grapples with emissions of carbon monoxide, nitrogen oxides, and particulate matter. Notably, the prevalence of over 2.5 million motorcycles in Dhaka contributes significantly to the city’s air pollution problem, as motorcycles tend to emit higher levels of pollutants compared to other vehicles. 

Migration and its Impact

Dhaka’s status as a major economic hub draws migrants from rural areas across Bangladesh. While the city offers job opportunities and the promise of a better life, this migration places immense strain on its infrastructure, especially in waste management and traffic control. Consequently, air pollution has worsened as a result of increased population density and associated challenges.

Industrial Emissions

Industrial emissions are another major source of air pollution, accounting for about 20% of the total emissions. Dhaka houses various industries, including textiles, leather, and chemicals, which release pollutants into the atmosphere. The textile industry, in particular, has been identified as a significant polluter. The excessive water usage, coupled with untreated wastewater disposal into the city’s rivers and canals, contributes to both water and air pollution. 

Urban pollution: Dhaka, Bangladesh - Sheet3
world’s second most polluted capital_©www.dhakatribune.com

Air Pollution Crisis

The culmination of these factors has led to an air pollution crisis in Dhaka. The city consistently ranks among the worst in terms of air quality globally, with pollutant levels, such as PM2.5 and PM10, far exceeding WHO guidelines. For instance, while the WHO guideline for PM2.5 is 10 micrograms per cubic meter (µg/m3), Dhaka’s average PM2.5 level stands at a staggering 87 µg/m3. 

Waste burning is also a major source of air pollution, accounting for about 10% of the total emissions. Waste burning is commonly used to dispose of garbage, but it releases harmful pollutants into the air.

The World Health Organization (WHO) has ranked Dhaka as the 2nd most polluted city in the world. The city’s air quality is so bad that it can cause serious health problems, such as respiratory infections, heart disease, and cancer.

Water pollution

The main sources of water pollution in Dhaka are untreated sewage, industrial waste, and garbage dumping. Untreated sewage is a major source of water pollution, accounting for about 60% of the total pollution. Dhaka’s sewage system is overloaded and poorly maintained, and much of the sewage is discharged untreated into rivers and canals. Industrial waste is another major source of water pollution, accounting for about 20% of the total pollution. Garbage is often dumped into rivers and canals, where it can pollute the water and attract mosquitoes.

water pollution _©www. thethirdpole.net/

Soil pollution 

The main sources of soil pollution in Dhaka are the disposal of hazardous waste, including industrial by-products and agricultural chemicals. Hazardous waste is often disposed of illegally in Dhaka, and this can contaminate the soil and groundwater. Agricultural chemicals are also a source of soil pollution, as they can leach into the soil and contaminate crops.

Noise pollution 

The main sources of noise pollution in Dhaka are traffic, construction, and industrial activity. Traffic is the largest source of noise pollution, accounting for about 60% of the total noise. Dhaka is a very congested city, and the traffic noise can be very loud. Construction is another major source of noise pollution, accounting for about 20% of the total noise. There is a lot of construction activity in Dhaka, and the noise from construction can be very disruptive. Industrial activity is also a source of noise pollution, accounting for about 10% of the total noise.

Government Initiatives

In response to this pressing issue, the government of Bangladesh is taking significant steps to combat urban pollution. Initiatives include enhancing the public transportation system to reduce traffic congestion, promoting the use of electric vehicles to curb emissions, investing in more effective waste management practices, mitigating industrial pollution, Treating industrial waste before it is discharged into rivers and canals,

reducing garbage dumping and raising awareness about the importance of environmental protection.

A few examples of how architects are working to change the dynamic of urban pollution in Dhaka are given below. 

‘The Green Dhaka project: This project is a comprehensive plan to make Dhaka a more sustainable city. The project includes proposals for increasing the number of green spaces, improving public transportation, and promoting the use of renewable energy.

The project proposes to increase the number of green spaces in Dhaka by 50%. 

It also proposes to improve public transportation in Dhaka. This would be done by expanding the metro system, and by providing more buses and rickshaws.

Finally, the project proposes to promote the use of renewable energy in Dhaka. This would be done by installing solar panels on buildings, and by using wind turbines to generate electricity. Renewable energy is important for reducing air pollution and for mitigating climate change.

The Dhaka Climate Resilient Urban Design Guide: This guide provides recommendations for making Dhaka more resilient to climate change. The guide includes proposals for increasing the number of green roofs, planting more trees, and using more sustainable materials.

Green roofs are roofs that are covered with plants. They can help to improve air quality, reduce noise pollution, and regulate the temperature of buildings. Planting more trees can also help to improve air quality and reduce noise pollution. Using more sustainable materials can help to reduce the environmental impact of construction.

The Dhaka Vertical Forest: This project proposes a vertical garden that would help to improve air quality in the city. The garden would be made up of trees and plants that would absorb pollutants and provide shade.

The vertical forest would be built on the side of a tall building. It would be made up of a variety of trees and plants, including evergreens, deciduous trees, and flowering plants. The plants would help to absorb pollutants from the air, and would also provide shade and a place for birds and insects to live.

The Dhaka Floating Market: This project proposes a floating market that would be powered by renewable energy. The market would provide a space for people to buy and sell local produce and would help to reduce pollution from traffic.

There are many other projects underway, and more are being planned all the time. With continued effort, it is possible to make Dhaka a more sustainable and livable city.’ 

Conclusion

The urban pollution crisis in Dhaka is a complex issue driven by a convergence of factors, including rapid urbanization, population growth, inadequate green spaces, vehicular emissions, and industrial pollution. Addressing this problem requires a multifaceted approach that includes improved urban planning, stricter environmental regulations, investments in public transportation, waste management upgrades, and efforts to reduce industrial emissions. The urgent need to tackle urban pollution in Dhaka cannot be overstated, as it not only impacts the health and well-being of its residents but also contributes to broader environmental and climate concerns.

References:

  1. The World Bank (2023). Bangladesh | Data. [online] Worldbank.org. Available at: https://data.worldbank.org/country/bangladesh.
  2. ‌Dhaka City Corporation (2023). Annual Report 2022-2023.
  3. Un.org. (2019). UNdata. [online] Available at: https://data.un.org/.
  4. ‌www.airvisual.com. (n.d.). Empowering the World to Breathe Cleaner Air | IQAir. [online] Available at: https://www.iqair.com/.
  5. data.gov.bd. (n.d.). Bangladesh Open Data | Data For All. [online] Available at: http://data.gov.bd/.

Author

Hello! This is Zeba, a student pursuing her passion in the field of design and architecture. With the heart of an explorer always seeking new experiences that inspire her, she appreciates soaking in the beauty of the world around her and weaving words that stir the imagination. She truly believes that as architects it is our duty to make a difference that stands for generations to come.