Climate Change and Health Vulnerability in Korail and Rayer Bazar Slums, Dhaka, Bangladesh

In the crowded, humid heart of Dhaka, Bangladesh, the air itself tells a story of changing weather. For decades, scientists have understood that the planet is warming, but the true weight of this shift is felt most acutely in the places where people have the least protection. This is the realm of climate and health, a field that examines how rising temperatures, shifting rains, and extreme weather events translate into sickness and suffering for human beings. It is not just about the weather getting hotter; it is about how that heat interacts with the walls of a home, the quality of the water, and the ability of a community to cope. When a city grows faster than its roads, drains, and hospitals can handle, the people living in its most crowded corners face a perfect storm. They are exposed to the elements with nowhere to retreat, and their bodies bear the cost of a changing climate in ways that are immediate and often deadly.

A recent study by researcher Golam Sakib Intisher Prochsad brings this abstract danger down to the street level by looking at two specific neighborhoods in Dhaka: Korail and Rayer Bazar. These are informal settlements, often called slums, where millions of people live in tightly packed conditions. The researcher did not go out to collect new blood samples or survey every household; instead, they acted as a synthesizer, gathering and comparing dozens of existing scientific reports, studies, and data sets published between 2002 and 2026. The goal was to map out exactly how climate change harms health in these two communities, to see where the risks overlap, and to discover where the two neighborhoods differ in their ability to survive. By piecing together this mosaic of evidence, the study reveals that while both places face the same storm, they weather it in very different ways.

The picture that emerges is one of constant, overlapping threats. In these neighborhoods, the heat does not just sit in the air; it bounces off the tin roofs of the homes and gets trapped inside, turning small rooms into ovens. This is known as the urban heat island effect, where the city itself holds onto warmth longer than the surrounding countryside. For the people living there, this means their bodies are under constant strain. The study found that even a small rise in temperature variability can lead to a noticeable jump in emergency visits for heart and lung problems. Older adults and those working outdoors are hit hardest, their bodies struggling to cope with the fluctuating heat. When the monsoon rains arrive, the danger shifts from heat to water. Because the ground is often low-lying and the drainage systems are blocked or non-existent, rainwater pools on the streets and seeps into the living spaces. This standing water becomes a breeding ground for mosquitoes that carry dengue fever, and it contaminates the water sources people rely on for drinking and washing.

The research highlights a stark reality: the health risks are not just about the weather itself, but about the environment the weather hits. In these settlements, the lack of safe toilets and clean water means that when floods occur, the water that touches people is often filled with waste. This connection between flooding and disease is direct and severe. The study points out that when waterlogging happens, access to safe sanitation can drop by more than a third, forcing people to use facilities that are submerged or unusable. This leads to a sharp rise in diarrheal diseases, which are already a major killer in these areas. The same stagnant water that causes illness also fuels the spread of dengue, as the mosquitoes find endless places to lay their eggs in discarded containers and clogged drains. The evidence suggests that as temperatures rise and rains become more erratic, the transmission of these diseases will likely increase, putting more children and vulnerable residents at risk.

However, the study makes a crucial distinction between the two neighborhoods, showing that vulnerability is not the same everywhere. Korail, one of the largest settlements, has received more attention from researchers and non-governmental organizations. Because of this, there is more data available about its specific problems, and the community has access to some formal health services and infrastructure upgrades. In contrast, Rayer Bazar is a place where the scientific record is much thinner. There are far fewer studies dedicated to its specific climate-health challenges, and the residents rely heavily on informal coping mechanisms, such as sharing resources with neighbors or using traditional healers, rather than formal medical care. This gap in knowledge is itself a problem, because without clear data, it is harder to design the right solutions for Rayer Bazar. The study suggests that while both communities are struggling, the lack of specific evidence for Rayer Bazar means its unique needs might be overlooked in city-wide plans.

The human cost of these environmental failures extends beyond physical illness. The study found that the stress of living through heatwaves and floods takes a heavy toll on mental health. People who have been exposed to these extreme events report higher levels of anxiety and distress, particularly women and the elderly who often bear the burden of caring for families during crises. The fear of losing what little they have, combined with the physical discomfort of living in a flooded or overheated home, creates a psychological strain that compounds the physical dangers. The research indicates that this mental distress is a real and measurable outcome of climate exposure, yet it is often ignored in discussions about disaster response.

Ultimately, the paper argues that treating all slums as if they were the same is a mistake. The solutions that work in Korail, with its existing NGO support and slightly better infrastructure, may not work in Rayer Bazar, where the gaps are wider and the data is scarce. The study concludes that building resilience requires more than just general warnings about climate change; it demands specific, targeted actions for each community. This means upgrading drainage systems to handle heavy rains, designing housing that stays cooler, and creating health surveillance systems that can track diseases as they spread. It also means recognizing that the people in these neighborhoods are not just victims of the weather, but are already using their own resourcefulness to survive. The path forward, the research suggests, is to support these local efforts with better infrastructure and fairer policies, ensuring that the most vulnerable are not left to face the changing climate alone.