How two megacities stopped functioning at once
Record rainfall exposed more than a drainage failure in Dhaka and Chattogram. It laid bare decades of fragmented planning, delayed infrastructure projects and institutional shortcomings that have left Bangladesh's two largest cities increasingly vulnerable to flooding.
Bengalis often welcome the rain after weeks of heat. That changes when heavy rain continues for days. In Dhaka, days of rainfall left many roads submerged, disrupting public transport and bringing large parts of the city to a standstill.
Chattogram is facing a catastrophic waterlogging crisis. On 8 July, 2026, Chattogram recorded 412.3 millimetres of rain in a single day, the heaviest in 42 years, according to the Bangladesh Meteorological Department. Roads in Agrabad and Muradpur disappeared under waist-deep water. A Cox's Bazar-bound train sat stranded with around a thousand passengers on submerged tracks, and Flights bound for Shah Amanat International Airport were diverted to Dhaka.
When it rained too heavily, two megacities stopped functioning at once.
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Three days earlier, the Economist Intelligence Unit (EIU), the research and analysis arm of The Economist magazine, had released its Global Liveability Index 2026, ranking Dhaka 171st of 173 cities with an overall score of 42 out of 100—third from the bottom, above only Tripoli and war-ravaged Damascus.
But the overall ranking hides a more troubling figure. Dhaka's infrastructure score was 27, the lowest among its five category scores and the lowest infrastructure score of any city in the bottom 10. Damascus, a capital city devastated by years of war, scored higher than Dhaka on infrastructure.
The city drowned its own drainage
Dhaka's flooding is the result of decades of unchecked urbanisation, the loss of canals and wetlands, and inadequate investment in drainage infrastructure.
The capital was built on water. By various official counts it had between 50 and 65 canals, most of them interlinked and flowing towards the four rivers that ring the city. Today, Dhaka Wasa's records list 26; only 24 remain identifiable, and some surveys put the number of genuinely functional canals in the low teens.
The River and Delta Research Centre estimates the capital has lost close to 120 kilometres of canal length to encroachment and landfill. The Centre for Environment and Geographic Information Services found that Dhaka lost 75% of its perennial wetlands in four decades, shrinking from 15,000 hectares in 1967 to 5,282 hectares now.
Concrete took their place. The 2015 Drainage Master Plan assumed 40% of rainfall would soak naturally into the ground; unchecked construction has since sealed the surface, forcing almost all runoff onto a drainage network never built to carry it.
Dhaka now has roughly 2,200 kilometres of drains, but planners say many run at less than half their intended capacity, clogged by the 7,000 tonnes of waste the city produces each day, 15% of it plastic.
In April this year, the two city corporations mapped 141 waterlogging hotspots. Money was never the constraint. Hundreds of crores have gone into canal recovery and drains, including Tk262 crore over four years to 2024 alone. The result is a city of 23,234 people per square kilometre that floods after a few hours of rain.
Chattogram bought a solution and it did not work
If Dhaka's failure is neglect, Chattogram's is expenditure without planning.
Since 2017, three agencies have undertaken four mega projects to address the port city's waterlogging at a combined cost of around Tk14,000 crore, of which roughly Tk10,000 crore has already been spent.
The flagship Chattogram Development Authority canal project, implemented by the Bangladesh Army's engineering brigade, was approved at Tk5,616 crore for completion by June 2020. It is now estimated to cost Tk8,626 crore, a 54% increase, and its completion deadline has been extended repeatedly. The latest proposed extension would push it to 2028.
The project's shortcomings were evident from the outset. It began without a feasibility study, did not follow the Chattogram Development Authority's 1995 master plan, and excluded 21 of the city's 57 canals. Those canals remain blocked, contributing to flooding in neighbourhoods such as Chawkbazar, Katalganj and Agrabad, even as officials describe the works as "nearly complete".
Siltation and poor waste management have reduced canal carrying capacity by about 40%, while the retention ponds proposed in the 1995 master plan were never constructed. "The CDA does not have drainage experts, so the work was handed over to the Army," Jerina Hossain, a Chattogram Development Authority board member and urban planner, told The Business Standard. Delwar Majumder, former president of the Institution of Engineers, Bangladesh, Chattogram Centre, has said the project was flawed from the beginning.
The Economist Intelligence Unit (EIU), the research and analysis arm of The Economist magazine, had released its Global Liveability Index 2026, ranking Dhaka 171st of 173 cities with an overall score of 42 out of 100—third from the bottom, above only Tripoli and war-ravaged Damascus.
The bill is paid downstream
The impact of those figures is reflected in the human toll.
As of 11 July, the death toll across five districts of Chattogram division had reached 39, with 9.28 lakh people affected, according to the Ministry of Disaster Management and Relief. Cox's Bazar recorded 23 deaths, including 13 Rohingyas.
More than 500,000 people were marooned in Satkania and Banshkhali alone. By the city corporation's own estimate, 22 of Chattogram's 41 wards are prone to flooding during heavy rain, affecting more than 3.1 million of the city's six million residents.
The impact is not shared evenly. One study found that in severe flood years, poor families in Dhaka lose up to 8% of their annual income because of flood damage, lost workdays and diseases caused by stagnant water.
A long-standing problem
The underlying problems have long been documented.
Urban planners have for years warned that Dhaka's drainage system is managed by dozens of agencies under multiple ministries without a single coordinating authority, and that Chattogram's waterlogging projects were based on flawed assumptions.
The underlying problems have long been documented. Urban planners have for years warned that Dhaka's drainage system is managed by dozens of agencies under multiple ministries without a single coordinating authority, and that Chattogram's waterlogging projects have been delayed by inadequate planning and repeated revisions.
