Disaster Vulnerability Mapping for a Densely Populated Coastal Urban Area: An Application to Mumbai, India

Coastal urban cities frequently face multiple hazards, including potentially disastrous extreme events. To combat this, vulnerability assessment is essential to developing an effective mitigation strategy. This study proposes a framework to assess the vulnerability of any densely populated urban area to disasters by considering both the population and the assets that are at risk. A set of indicators is also proposed to assess the vulnerability of social and socioeconomic systems, infrastructure, critical facilities, and adaptive capacity. The components of vulnerability were evaluated individually, using an accessible open source geographic information system at a fine 1-km grid scale, providing an insight into the spatial variability of the vulnerability. The optimal weight for individual indicators was assigned using data envelopment analysis to minimize subjective judgment and establish confidence in the results obtained. To decorrelate and reduce the dimensionality of the multivariate data, principal component analysis was performed. The proposed methodology was demonstrated on the twenty-four wards of Mumbai under the jurisdiction of the Municipal Corporation of Greater Mumbai and showed the mideastern part of Mumbai as the most vulnerable—mainly due to the increase in population and the marginal workers' ratio. A reduction in social vulnerability has been observed, however, across the city through improvement in the literacy rate and the main workers' ratio.