Karachi’s worsening urban heat is no longer just a seasonal discomfort and could turn into a major public health crisis if urgent action is not taken, a senior community health expert has warned.
Prof Zafar Fatmi, who heads environmental occupational health and climate change at Aga Khan University’s Department of Community Health Sciences, said the city’s urban heat effect appears to be growing more intense due to both climate change and the way Karachi is expanding.
He said rising concrete cover, denser construction, traffic congestion, shrinking green spaces, and the loss of trees are causing the city to absorb and retain more heat, especially in crowded urban areas.
According to Prof Fatmi, recent studies show Karachi has one of the strongest urban heat island effects in Pakistan. A 2026 multi-city study found the city had the highest urban-rural temperature gap among major cities, at around 4.5 degrees Celsius, linking vegetation loss with higher land surface temperatures.
He said the danger is even greater at street level, where actual heat exposure can be much higher than official city temperatures. Research in Karachi found that delivery riders and rickshaw drivers were exposed to temperatures significantly above the city average, especially under direct sunlight.
Prof Fatmi said the warning signs are already visible, with nights staying hot, outdoor workers tiring earlier, and more people reporting dehydration, dizziness, headaches, poor sleep, fainting, and fatigue.
He warned that the risk is especially high for children, elderly people, pregnant women, traffic police, vendors, construction workers, delivery riders, rickshaw drivers, and those living in poorly ventilated homes. People with heart disease, diabetes, kidney disease, lung conditions, and high blood pressure are also more vulnerable.
He added that heat becomes even more dangerous when combined with Karachi’s air pollution. According to him, residents are often exposed to both at the same time in traffic-heavy, dusty, and congested areas, increasing pressure on the lungs, heart, and overall health.
The expert also warned that rising temperatures can worsen the spread of infections by creating better conditions for mosquitoes, food spoilage, unsafe water storage, and contamination, particularly in areas with weak sanitation, drainage, and waste management.
He said Karachi now needs a serious heat-health action plan that includes public alerts in local languages, shaded bus stops, public drinking water points, cooling spaces, school guidance during heatwaves, and stronger hospital preparedness.
At the same time, he said the city must address the root causes by protecting mature trees, expanding green spaces, reducing unnecessary concrete, improving public transport, controlling dust and emissions, and making heat assessments mandatory for major urban projects.
Prof Fatmi warned that without coordinated action, extreme heat will continue to quietly damage public health, productivity, and the daily lives of those most exposed.