Spatio-Temporal Dynamics of Urban Environmental Stress in the Rapidly Developing Coastal-Industrial Landscape of Thoothukudi, India

Recent studies indicate that the intensification of Urban Heat Island (UHI) effects is significantly altering the thermal equilibrium of rapidly industrialising coastal cities. However, the multi-dimensional mapping of persistent environmental criticality through the integration of thermal and biophysical stressors has remained underexplored. This study investigates the spatio-temporal dynamics of urban stress in Thoothukudi, India, by developing an Urban Environmental Stress Index (UESI) that synthesises Land Surface Temperature (LST), Normalised Difference Built-up Index (NDBI), and Normalised Difference Vegetation Index (NDVI). Over a six-year period (2020–2025), a multi-stage geospatial workflow was implemented, utilising Ordinary Least Squares (OLS) regression and Global Moran’s I to evaluate the influence of impervious surface density (ISD) and green space density (GSD) on environmental criticality. Our findings reveal that UESI saturation unexpectedly peaked in the 5–10 km transitional buffer (15.43% of the area), while the urban core (Zone 1) exhibited the highest ISD value at 58.91%. OLS regression confirmed a strong distance-dependent relationship, with residuals stabilising in the 20 km buffer, indicating that surface characteristics increasingly govern stress patterns in the periphery. Global Moran’s I values (ranging from − 0.228 to 0.496; p > 0.05) confirmed the absence of significant spatial autocorrelation in residuals, validating the model’s spatial independence. The study identifies distinct Urban Stress Corridors and proposes a targeted spatial strategy to enhance climate resilience by prioritising green-blue infrastructure in high-vulnerability transitional zones. These results offer a robust framework for sustainable urban planning in emerging industrial hubs facing extreme thermal challenges.