A Geospatial Framework for Assessing Urban Environmental Criticality: A Case of Kidderpore, Kolkata

Abstract. Urbanization has emerged as a dominant driver of environmental transformation, leading to increased surface temperatures, loss of vegetation, and pressure on infrastructure systems. This kind of rapid transformation often leads to environmental degradatio n, thus impacting livelihood. This research aims to quantify the impact of rapid urban growth on the environment through the Environmental Criticality Index (ECI) derived from Landsat 8 datasets. The Normalized Difference Vegetation Index (NDVI), Normalized Difference Built-up Index (NDBI), and Land Surface Temperature (LST) were calculated over the Kidderpore area in Kolkata metropolitan city in 2014, 2019, and 2024. The NDVI, NDBI, and LST were used to estimate the ECI in the above-mentioned periods. The calculated ECI was categorized into five classes: Very low, low, moderate, high, and very high. The results revealed that the area under very low ECI was 2.39 sq. km. in 2014, 1.88 sq. km. in 2019, and 1.51 sq. km. in 2024. The area under very high criticality was observed to be 3.84 sq. km. in 2014, 4.24 sq. km. in 2019, and 4.38 sq. km. in 2024. In the very highly critical areas, the mean LST in 2014 was observed to be 43.61°C. The mean LST in such areas increased to 45.69°C in 2019 and to 47.51°C in 2024. The mean NDBI values in very highly critical areas varied from -0.24 to 0.20 in 2014, -0.22 to 0.29 in 2019, and -0.17 to 0.38 in 2024. The research would help with sustainable urban planning through environmental risk monitoring.