Spatio-Temporal Review of Urban Green Space Degradation at Administrative Level Using Geospatial Techniques and Multi-criteria Decision Analysis: A Case Study of Kolkata Urban Agglomeration

The metropolitans of developing countries are experiencing an unplanned manner of urbanization that has led to a pessimistic state of deterioration of urban green space. But an ideal holistic methodological framework to quantify several facets of urban green space at the administrative level is still debatable. This study, therefore, intends to discern the decadal (1990–2020) change in the spatial distribution of the areal coverage, clustering, fragmentation and connectivity of urban green space in the administrative units of Kolkata Urban Agglomeration region using an experimental integrative methodology of combining remote sensing, landscape metrices and multi-criteria decision analysis. Using 9 landscape metrices, the result shows green space patches, in all the administrative units have experienced a certain degree of reduction in areal extent and connectivity with an increase in fragmentation. Moreover, using Mann–Kendall’s Test with Sen’s Slope estimator, it has been found that distance from the transport network plays a crucial part in the amount of change in landscape metrices. Finally, a Green Space Degradation Index has been formulated using the analytical hierarchy process, which shows the north-eastern and south-western municipalities have a higher degree of green space degradation, whereas the non-municipal areas have the least. This study not only has quantified the spatial intensity of deterioration of green space in the Kolkata Urban Agglomeration region, and such methodology might act as a comprehensive aid to policymakers and local urban bodies for a better understanding of urban green space degradation and formulation of sustainable management measures at the administrative level.