In southwestern Nigeria, especially along the Lagos–Ogun–Oyo corridor, the number of informal settlements and slums has been growing rapidly. This area is an important economic center with many industries, businesses, and job opportunities, which attracts large numbers of people. As more people move there, many end up living in unplanned communities that lack proper infrastructure and basic services.

In states such as Ogun and Oyo, which border Lagos, these settlements are becoming increasingly common. Many residents live in overcrowded housing and face problems such as poor sanitation, unsafe drinking water, and limited waste management. These conditions also make communities more vulnerable to climate-related problems such as extreme heat and flooding.

As a result, people living in these areas often experience health problems, including respiratory illnesses caused by poor air quality and diseases linked to contaminated water. Climate change can worsen these risks by increasing heat and environmental stress in already vulnerable neighborhoods.

Although researchers, governments, and organizations have tried to address these issues through policies and programs, progress has been limited. Challenges such as insufficient funding, weak enforcement of regulations, and poor coordination between different groups continue to slow improvements.

To address these problems, a broader and more coordinated approach is needed. This could include involving communities in city planning, providing small financial support to help residents improve their living conditions, and developing programs that help communities adapt to climate change. Cooperation between governments, non-governmental organizations, and local residents will be essential to create healthier, safer, and more sustainable urban environments.

The rapid expansion of informal settlements and slums in southwestern Nigeria, particularly along the Lagos-Ogun-Oyo corridor, underscores the critical challenges posed by rapid urbanisation and population growth in this major economic hub of West Africa. This corridor, home to key infrastructure, industries, and economic activities, has seen a significant rise in unplanned communities due to its economic opportunities. In particular, Ogun and Oyo states, both sharing borders with Lagos, have become hotspots of these communities, characterised by inadequate housing, poor sanitation, unsafe drinking water, and heightened vulnerability to climate-related hazards. In this viewpoint, we examine the health and environmental challenges faced by residents in these informal settlements, including respiratory illnesses, waterborne diseases, and climate-related health risks exacerbated by poor air quality and extreme heat. Despite various research efforts, policy reforms, and programmatic interventions, challenges such as limited funding, inadequate enforcement, and a lack of coordination among stakeholders persist. We propose a holistic, multi-sectoral approach that could improve living standards and health outcomes through community empowerment, participatory urban planning, microfinance initiatives, and climate resilience programmes. We note that this requires collaborative efforts from government, non-governmental organisations, and local residents to create sustainable and resilient urban environments.