Mumbai Floods: Climate Change and Urbanisation Outpace Infrastructure Upgrades
The southwest monsoon has been highly active over western India, with moisture-laden southwesterly winds sweeping across the Western Ghats and delivering intense rainfall along the Konkan coast. Offshore weather systems have routed additional moisture over Mumbai and surrounding areas. In urban areas, rainfall intensity often matters more than total volume. Mumbai can generally absorb moderate rainfall over several hours, but its drainage system, like many Indian cities, cannot handle several hundred millimetres in short bursts.
Heavy rainfall also overwhelmed river catchments in parts of Maharashtra, including around Nashik. High tides reduced the efficiency of Mumbai's stormwater drainage, worsening flooding. The Mumbai-Pune rail services were suspended after landslides in the Bhor Ghat, and flights were affected. Closures of the Mumbai-Pune expressway and the Mumbai-Goa highway, along with significant flooding on the Mumbai-Ahmedabad expressway, highlighted the increasing erraticity of monsoon rainfall, vulnerabilities in linear infrastructure projects, and how natural disasters are compounded by cascading failures. A chawl collapse in Mankhurd claimed the lives of five children.
Mumbai lies on a peninsula built mostly on reclaimed land, former marshes, tidal flats, and low-lying coastal areas. This geography creates a higher risk of flooding when rainfall coincides with high tide. Decades of haphazard urbanisation have encouraged water runoff rather than absorption, forcing drains to handle more water than their design limits. After the July 2005 floods, when Mumbai received 944 mm in 24 hours, the city launched the BRIMSTOWAD project, widened drains, installed pumping stations, and undertook pre-monsoon de-silting. Many of these works remain incomplete, and some completed upgrades are based on assumptions about the monsoon that climate change has since undermined.
Officials have argued that pre-monsoon de-silting helped reduce flooding in parts of Mumbai. However, water on the Mumbai-Ahmedabad expressway, the chawl collapse, deadly tree falls in Kurla and Aarey, lack of redundancies in public transport, and the Brihanmumbai Municipal Corporation's (BMC) belated advisory to builders to halt hazardous construction indicate governance lapses. Accountability in Mumbai remains split across the BMC for local drainage and roads, the India Meteorological Department (IMD) for forecasting, the National Disaster Response Force (NDRF), two railway zones, the state government, and highway authorities.
Overall, the city has improved at shutting down to save lives and minimising the death toll during extreme events. But as climate change and urbanisation evolve faster than infrastructure upgrades, simply waiting for system capacity to catch up to demand will be a failing strategy.
