Towards climate-responsive cities: developing a heat vulnerability index for Jodhpur City, India.

Introduction: Climate change intensifies heat risks in urban areas, and spatial vulnerability assessments are essential for informing targeted adaptation strategies. We developed a preliminary ward-level Heat Vulnerability Index (HVI) for Jodhpur City, India, integrating exposure, sensitivity, and adaptive capacity domains to characterize hyperlocal variation in heat vulnerability. Methods: A two-step Principal Component Analysis (PCA) was applied to integrate 11 standardized socio-demographic and environmental indicators into composite scores. First, domain-specific PCA reduced dimensionality by identifying principal components that captured maximum variance within each domain. Second, standardized weights for individual indicators were derived from their loadings and contributions to variance within the retained components. Weighted domain scores were combined to calculate the overall HVI. Results: Heat vulnerability varied across Jodhpur's 80 wards, with 25 highly vulnerable, 35 moderately vulnerable, and 20 with low vulnerability. Exposure was driven by an inverse relationship between land surface temperature (LST) and population density. Wards with higher population density tended to have lower LST values owing to shaded streets and traditional adaptations such as reflective roofs, while sparsely populated wards had higher LST. Sensitivity findings highlighted demographic and socio-economic heat susceptibility factors, including higher proportions of children aged 0-6 years, females, and marginalized caste groups. Adaptive capacity was primarily shaped by higher literacy rates, proximity to urban health centers, greater green cover, and presence of water resources. Conclusions: The preliminary HVI improves understanding of heat vulnerability at the ward-level. Our findings can inform decision-making to ensure equitable heat adaptation in Jodhpur City.