Efforts to combat air pollution, while beneficial for public health, are inadvertently contributing to a rise in urban heatwaves. A new study highlights the climate trade-offs associated with cleaner air, suggesting that reduced aerosol particles, which previously reflected sunlight, are now allowing more solar radiation to reach the Earth's surface in cities. This intensifies the urban heat island effect and increases the frequency and severity of heatwaves. Researchers emphasize the need for comprehensive strategies that address both air quality and climate change to mitigate these unintended consequences.