Urban expansion and wetland shrinkage estimation using a GIS-based model in the East Kolkata Wetland, India

•LULC analysis shows mainly built-up land expansion consumes urban peripheral wetland.•Infrastructural activity and urban developmental projects are the active agents of wetland shrinkage.•Markov Transition Probability Matrix has shown only 39 percent of wetland area will remain in 2025.•Simulated 2025 wetland surface shows extensive outlier loss.•The absence of institutional coordination, financial support, and land use regulations are the main determinants of policy failure.