Dhaka: The megacity no one planned for is now the world’s 2nd-largest

Have you ever wondered why Western travel influencers flock to Dhaka, of all places? The Bangladeshi countryside, I get, but Dhaka? As a voracious consumer of travel content, yours truly has given it some thought and I think I have an answer. 

To stand at a traffic intersection in Farmgate or wrestle through the human tide of Gulistan during rush hour is to witness a phenomenon that seemingly defies the laws of physics. It is a sensory assault of clamouring rickshaw bells, the cacophony of hundreds of vehicle horns, the hiss of dying buses idling, and a density of humanity that feels less like a city and more like a compression of an entire nation into a singular, painfully throbbing point. 

For years, residents have felt the walls closing in, the air growing heavier and the roads becoming more gridlocked. Now, the United Nations has confirmed what every commuter in Bangladesh already knew in their bones: Dhaka is exploding.

According to the UN's recently released World Urbanization Prospects 2025, Dhaka has officially become the second-largest city on the planet. With a population now estimated at a staggering 36.6 million, the Bangladeshi capital has leapfrogged Tokyo — the former heavyweight champion of urban density — and sits just behind Jakarta, Indonesia, which holds the top spot with 41.9 million residents. 

But while Jakarta's reign at the top is projected to be temporary, Dhaka's ascent appears relentless. By 2050, the UN predicts Dhaka will claim the title of the world's most populous city, home to an unfathomable 52.1 million souls.

A city bursting at the seams

Dhaka's expansion is not merely a story of natural urbanisation or the allure of city lights; it is a story of survival. The city acts as the primary lifeboat for a nation on the frontlines of the global climate crisis. Every day, the city absorbs a floating population that arrives not just with dreams of prosperity, but often with the trauma of loss. 

They flee the vanishing islands of the Meghna estuary, the salinised soil of the southwest, and the eroded riverbanks of the north. They end up in the sprawling slums of Korail or the precarious settlements of Kamrangirchar, trading the risk of drowning for the certainty of urban squalor.

The drivers of this migration are complex, fueled by a mixture of economic necessity and environmental collapse. The number of people migrating to Dhaka from villages and towns is increasing every day, a trend that demographers have watched with growing alarm. 

Dhaka University's former Chair of the Department of Population Sciences, Mohammad Mainul Islam, explained several reasons behind this trend in an interview with Prothom Alo. He noted that the influx is overwhelming the natural birth rate of the city itself.

"The rate of migration from rural areas to Dhaka is more than twice our population growth rate," Mainul Islam told the newspaper. "Job opportunities in rural areas are very limited, so many come to Dhaka in search of work. People are also moving due to climate change–related environmental risks. As agricultural land shrinks, many landless people move to Dhaka. Besides, many come for education, healthcare, and other urban facilities."

This "push factor" creates a demographic pressure cooker. Unlike the urbanisation of the West during the Industrial Revolution, which was driven by factory jobs pulling workers in, Dhaka's growth is largely driven by rural desperation pushing people out. 

The result is a city that is growing faster than it can build, creating a disjointed urban fabric where luxury high-rises sit uncomfortably next to tin-roofed shanties. 

The livability crisis

The statistics of Dhaka's sheer size mask the grim reality of its living standards. In the lexicon of urban planning, Dhaka is a "primate city" — it disproportionately dominates the country's economy and politics, hoarding resources while simultaneously collapsing under the demand for them. The infrastructure gap is not just wide; it is a chasm. 

While cities like Tokyo and Seoul boast near-perfect sewage coverage and drinking water straight from the tap, Dhaka struggles to provide safe water to its periphery. The Buriganga River, the city's historical lifeline, is biologically dead, choked by tannery waste and untreated sewage, a dark mirror of the city's struggle to manage its own waste.

The pressure on housing and basic services has reached a breaking point. Uswatun Mahera, Assistant Professor in the Department of Local Government and Urban Development at Jatiya Kabi Kazi Nazrul Islam University, highlighted the systemic failure in comments to the Bangladeshi press. She painted a stark picture of the logistical nightmare facing city planners.

"Every year, about 500,000 people come to Dhaka. Arranging housing for them has become a major challenge," Uswatun Mahera told Prothom Alo. "The increasing population is polluting Dhaka's air and water. Services like transport and waste management are becoming ineffective. Unplanned expansion is obstructing the ability to meet citizens' basic needs."

This lack of execution is visible in every corner of the metropolis. The city's air quality index frequently tops the global charts for toxicity, a hazardous haze that settles over the city in winter. 

The amenity-shaped hole in Dhaka's beating heart

To understand the severity of Dhaka's position, one must look at what a city of 36 million should look like compared to what Dhaka is. When compared to its peers on the UN list, Dhaka lags significantly in public amenities. Tokyo, with 33.4 million people, moves millions daily through one of the world's most complex and efficient rail networks. 

Dhaka, with a larger population, has only recently inaugurated its first Metro Rail line. While a step in the right direction, it is a drop in the ocean for a city of this magnitude. The vast majority of the population still relies on a chaotic fleet of crumbling buses and rickshaws, leading to gridlock that eats up an estimated significant percentage of the country's GDP annually in lost working hours.

Beyond the roads, the city's environmental amenities reveal an even deeper crisis. Global urban standards suggest that a livable city requires approximately nine square metres of green space per resident to mitigate heat and provide psychological relief. Dhaka offers barely a fraction of a square metre. 

The city has become a heat-trapping labyrinth of concrete and glass, where the "urban heat island" effect makes the humid summers feel lethal. While residents in Shanghai or Seoul can access manicured public parks and riverfront promenades, Dhaka's children are growing up in a city where playgrounds are being cannibalised by real estate developers

Furthermore, water security remains a looming threat. The UN report notes that severe water shortages are already plaguing cities like Tehran, where authorities have introduced rationing for its nine million residents. 

Dhaka faces a paradoxical dual threat: the depletion of its groundwater table due to excessive extraction and the risk of flooding from poor drainage. The city is sucking its aquifers dry while simultaneously failing to manage stormwater, leading to waterlogging after even moderate rains that brings the city to a standstill.

A tale of two cities: Jakarta and Dhaka

The comparison with Jakarta, the only city currently larger than Dhaka, offers a terrifying cautionary tale. Jakarta is sinking — literally. Excessive groundwater extraction and rising sea levels threaten to submerge a quarter of the Indonesian capital by 2050. 

The crisis is so severe that the Indonesian government has taken the radical step of building a completely new capital, Nusantara, on the island of Borneo. They are effectively retreating from their megacity.

Bangladesh, however, does not have the luxury of a Borneo. It is a land-scarce delta where every square inch is contested. Dhaka cannot be abandoned; it must be fixed. Yet, the trajectory is ominous. While Jakarta is projected to shrink back to second place by 2050 as its population stabilises, Dhaka is projected to keep growing, absorbing another 15 million people. 

This divergence suggests that while other megacities are reaching a plateau or actively managing their density, Dhaka is still in the accelerating phase of its growth curve, with little safety net in place.

Decentralise or die

If Dhaka is to avoid the dystopian future predicted by the 2050 data, it must undergo a radical transformation in how it is governed and planned. 

The consensus among experts is that the current model of centralisation is unsustainable. Hospitals, universities, high courts, and corporate headquarters are all clustered within the capital, creating an unbreakable magnetic pull.

Professor Mainul Islam was emphatic about the need for a structural overhaul. 

Recommending the formulation of a new urban policy, he told the local press, "All institutions related to public services need to be strengthened. At the same time, commercial activities must be relocated outside Dhaka." 

This sentiment echoes a long-standing demand from urban planners: until the government decentralises power and economy to secondary cities like Chittagong, Sylhet, or Khulna, the migration flow will never stem.

Moreover, the approach to urban planning must shift from reactive to proactive. It is not enough to build flyovers after the traffic has already choked the roads. 

"Sustainable and integrated planning is required," says Uswatun Mahera. She argues that the state cannot leave the development of the city to private interests and chaotic market forces. "A sustainable and coordinated plan is essential to solve this. The government must take the lead," the urban planner added.

It is painfully obvious the crisis is not coming; it is already here. The preparations to house, feed, and transport the next 15 million people should have begun yesterday, and without immediate government intervention, the world's next largest city may well become its most unlivable.