Excess rainfall costs Mumbai $1.2 billion and caused 2,700 deaths every year: Report

Extreme and erratic weather events continue to expose weak spots in India’s urban infrastructure as well as public health, leaving millions susceptible to disease and displacement

Severe rains killed far more people in Mumbai than listed in public records, accounting for roughly 8% of all deaths in India’s financial capital during the monsoon season and $1.2 billion in losses every year in the decade through 2015, a new study shows.

As many as 2,718 deaths occurred every year during the monsoon season between 2006 and 2015 putting it on par with cancer deaths in those months, according to research published Wednesday in Springer Nature, an international science journal.

Causes of death included drowning, electrocution and disease outbreaks while conditions such as diarrhea, tuberculosis and hypertension were exacerbated during severe flooding, it said.

“There are many other areas which are now experiencing flooding, which they did not experience maybe 10 years back,” Archana Patankar, founder of consultancy Green Globe and co-author of the study, said in an interview. “So it is only logical to expect that things would have worsened” since 2015.

Extreme and erratic weather events continue to expose weak spots in India’s urban infrastructure as well as public health, leaving millions susceptible to disease and displacement. India ranks ninth among countries most impacted by climate disasters since 1995, according to the Climate Risk Index 2026 published by GermanWatch.

Torrential rain has been testing India’s infrastructure push, championed by Prime Minister Narendra Modi - from highways and flyovers to airports –  whose administration has set aside planned capital expenditure of 11.2 trillion rupees ($126 billion) for the year ending March 2026.

Flooded Subway Station

In May, floodwater coursed into a newly inaugurated subway station in Mumbai, overwhelming the city’s British-era drainage system and disrupting the city’s train services. Such incidents revive memories of the city’s catastrophic 2005 deluge, which killed at least 400 people.

Using high-resolution data on rainfall, sea tides, and death records, the Springer Nature researchers estimated the mortality costs of rainfall in Mumbai – representing the total economic value attributed to each life lost – at $12 billion for the entire decade they examined. They classified children, women and adults over 65 as the most vulnerable groups. About 80% of those affected lived in Mumbai’s slums.

The city has started using an early-warning system for forecasting floods, while researchers are turning to hyperlocal data to pinpoint its most vulnerable communities, said Subimal Ghosh, a professor at the Indian Institute of Technology Bombay and a corresponding author of the study.

Minimize Losses

For Patankar, the approach helps minimize losses and aids in planning rescues, but it is “not enough as the first line of response.” “There’s a need for better infrastructure, a more responsive health care system, and improved waste management, she said.

The study also warns that 107 cities in developing countries face acute weather risks. That exposes 560 million people to life-threatening conditions, it added, underscoring the scale of the global risk.

The study’s authors call for coordinated, long-term investment in climate adaptation, warning that “a rise of 40 centimeters in sea level would result in 56% increase in excess deaths.”