The saying is that a “river will always reclaim its floodplain” and that the “monsoon is not a surprise—it is a season to prepare for, not a crisis to react to”. Yet, year after year, the rains bring the same scenes of chaos—waterlogged roads, traffic snarls, flooded neighbourhoods, disrupted lives, deaths, and renewed promises of better preparedness.
Despite their differing geographies, India’s major cities such as Mumbai, Bengaluru, Chennai and Delhi share a common problem: decades of unplanned urbanisation, shrinking wetlands, encroachment on natural drainage channels and ageing civic infrastructure have left them increasingly vulnerable to heavy rainfall.
Adding to the challenge is climate change. A warming atmosphere holds more moisture, increasing the likelihood of short-duration, high-intensity rainfall that can overwhelm drainage systems designed for historical rainfall patterns.
On Sunday, at least six people, including five children, were killed after a group of buildings collapsed in Mumbai’s suburbs, adding to the toll from heavy rains that have battered the country’s financial capital this monsoon.
While Mumbai’s vulnerability is also compounded by its coastal location and tidal conditions, the majority of cities have altered their natural terrain, reducing their ability to absorb and drain rainwater.
Experts say Mumbai’s ageing British-era drainage network and low-lying topography, shaped by historical land reclamation, are unable to cope with intense rainfall. Rapid urbanisation, shrinking mangrove cover, loss of green spaces, and widespread concretisation have further reduced groundwater recharge and increased surface runoff. Plastic waste and solid garbage frequently choke stormwater drains and nullahs, preventing water from flowing into the Arabian Sea.
In Bengaluru, rapid expansion driven by the IT boom has encroached upon lakebeds, wetlands and valley zones that once formed an interconnected chain of lakes capable of storing and channelling excess rainwater. The city’s stormwater channels have been narrowed, diverted or blocked by construction, leaving many neighbourhoods vulnerable to flooding.
Chennai has similarly witnessed large-scale urban expansion over marshlands and other natural catchments, eliminating the wetlands that once acted as natural sponges during heavy rainfall.
Delhi faces an equally persistent challenge. Along with poor maintenance and clogged drains, much of the capital’s primary drainage infrastructure is old and ill designed to handle today’s population, rapid urbanisation, increased paved surfaces or the mounting burden of construction debris and plastic waste that routinely blocks drains during the monsoon.
Beyond infrastructure gaps, critics also point to weak urban disaster management and fragmented institutional coordination. Early warning systems, pre-monsoon desilting drives and emergency response mechanisms are often inconsistently implemented across agencies, leading to delayed responses, inadequate preparedness and avoidable disruptions when heavy rainfall hits.