Urban ecological corridors (UECs) as sustainable paths to climate change adaptation and urban resilience: Reflections from Kolkata, India

Climate change and biodiversity loss have emerged as interconnected challenges driven by rapid urbanisation and ecological degradation. Indian metropolitan cities, including Kolkata, have experienced significant environmental fragmentation and loss of blue–green cover, which increased vulnerability to urban flooding and heat stress. In response, this study proposes an integrated urban ecological corridor (UEC) framework as a strategic component of blue–green infrastructure (BGI) to support climate resilience, ecological connectivity, and biodiversity conservation in dense urban contexts. The study adopts a multi-scalar GIS-based methodology integrating remote sensing, spatial analysis, and field validation. Spatial indicators including normalised difference vegetation index (NDVI), normalised difference water index (NDWI), normalised difference built-up index (NDBI), land use–land cover (LULC), urban blue–green spaces (UBGS), and canopy cover (CC) were analysed. Additional datasets including road networks, railway systems, canal systems, and cultural assets were integrated through buffering, overlay, proximity, and network analysis to identify ecological suitability and connectivity patterns. The findings reveal extensive ecological fragmentation and uneven distribution of blue–green spaces within the urban core. Based on spatial and functional characteristics, three UEC typologies were identified: eco-cultural along the two rivers, eco-biological integrating the canal system, and eco-mobility corridors along the major arterial roads and railways. The study concludes that strategically planned UECs integrated within the river–canal–road–railway network can serve as scalable and replicable solutions for climate-resilient urban transformation in rapidly urbanising megacities.