The study highlights significant risks to public health, urban infrastructure, and water resources due to the increasing intensity and duration of heatwaves. Cities in northwestern, northern, and eastern coastal regions of India are expected to face the most severe impacts. The probability of prolonged heatwaves, such as 6-day events, is projected to increase by several hundred per cent. This could exacerbate health issues, strain water supplies, and challenge urban infrastructure, particularly in densely populated areas.