Detection of Urban Changes in Mumbai, Jakarta, Hong Kong, Dhaka, and Beijing

This study analyzes urban expansion in three major Asian cities—Mumbai, Jakarta, and Hong Kong—between 2014 and 2024 using satellite-derived spatial indices. Four indices—NDVI, NDBI, BUI, and IBI—were applied to classify land cover and monitor annual changes in built-up and non-built-up areas. Six key metrics were used to track urban dynamics: built-up area, non built-up area, gain, loss, and overall change. Results indicate consistent urban growth across all cities, with Jakarta exhibiting the most significant expansion, while Hong Kong showed compact but steady development. In contrast, Mumbai revealed a surprising reversal in built-up trends, suggesting reclassification or partial vegetation recovery. The findings highlight varying urbanization patterns in South and Southeast Asia and underline the importance of spatial analysis for sustainable land-use planning. These insights contribute to a better understanding of coastal city dynamics and support evidence-based urban policy and planning.