In the past decade or so, starting with the Kedarnath tragedy in 2013, India has seen at least one major rainfall-related disaster every year (Table 1). In some years, like 2023, there have been multiple such incidents. The overall extent of monsoon rainfall over the country as a whole has had no bearing on the frequency or severity of extreme rainfall events. Such disaster-inducing rainfall incidents have happened even in the years when the overall rainfall during the season was relatively low, like in 2015, 2018 or 2023.
Table 1: In the past decade or so, starting with the Kedarnath tragedy in 2013, India has seen at least one major rainfall-related disaster every year.
Climate impact
IMD classifies any rainfall above 21 cm in a 24-hour period as extremely heavy rain. Typically, these account for less than 0.1% of all recorded rainfall events in the country. But their number seems to be increasing. In the four-year period between 2008 and 2011, for example, the maximum number of extremely heavy rainfall events in any season happened to be 64 (in 2008), according to IMD’s Annual Monsoon Reports. This number has been consistently, and comfortably, above 100 every year since 2017 (Table 2). In 2024, as many as 181 extreme rainfall events were recorded, while last year this number was 160.
Table 2: The number of extremely heavy rainfall events has been consistently, and comfortably, above 100 every year since 2017.
Part of this rise in the number of such events can be attributed to a lowering of the threshold for a rainfall incident to qualify as extremely heavy. Before 2016, only rainfall above 244.5 mm in a 24-hour period used to be classified as extremely heavy. This was lowered to 204.5 mm (sometimes rounded off as 21 cm) in 2016. But the increasing trend of such incidents is evident even at the higher threshold level.
More than the frequency, it is the increasing intensity of extreme rainfall events that is a cause of worry. Rains have been happening in shorter, and more intense, spells than earlier, raising chances of triggering a disaster.
A disaster a year
For more than a decade now, India has seen at least one major rainfall-induced disaster during the monsoon season. Some of these, like the Jammu and Kashmir flooding of 2014, the Chennai urban flooding of 2015 and the Kerala floods of 2018, have been record-breaking, once-in-a-century, or once-in-50-years, kind of events.
Almost every major city in the country — Delhi, Mumbai, Pune, Chennai, Bengaluru, Hyderabad, Kochi, Ahmedabad, Jaipur, Srinagar, Chandigarh, Gurgaon, Lucknow, Guwahati, Kolkata — has seen at least one major flooding event in the last 10 years, many of them getting classified as disasters. Cities like Chennai, Bengaluru, and Mumbai have witnessed multiple such events during this time.
Part of the blame for these kinds of urban flooding can, of course, be put on poor urban planning, unregulated development, construction on flood-plains, water bodies, or water channels, and municipal apathy. But it is also true that many of these disaster situations were triggered by unprecedented rainfall events.
In the first week of September of 2014, for example, Jammu and Kashmir received record-breaking rainfall. The overall rainfall for the month of September turned out to be the highest in over 100 years. The resultant floods in the state, possibly the worst ever in the last one century, killed over 280 people, damaged more than 2.5 lakh houses, and destroyed around 6.5 lakh hectares of crop area.
Similarly, the 2018 Kerala flooding in August was triggered by exceptionally high rainfall, the maximum since 1931, according to IMD records. Bengaluru has seen its 24-hour highest rainfall record broken twice in the last 10 years.
Difficult to predict
Such extraordinarily high rainfall is extremely difficult to predict. In many such instances, IMD is able to see the chances of very heavy rainfall and issues appropriate alerts, but whether the eventual rainfall would be in the range of 250 mm or 500 mm is something that cannot be said with any reasonable degree of certainty. This is an inherent limitation of the weather science itself. Weather is an extremely chaotic system, with very small changes in initial conditions giving rise to big differences in the end result.
A denser observational network, better modelling, and increase in computational capabilities can help in improving the forecasts, but a complete elimination of uncertainty is not possible. The more granular the forecast, in time as well as in location, the greater is the uncertainty. It is fairly established now that climate change is further exacerbating this uncertainty. Under the influence of climate change, extreme weather events have become more frequent and more intense, posing a much bigger challenge to meteorologists.
This trend is being seen globally, not just in India. And it is not restricted to rainfall events. Other weather events, like drought or heatwaves, have also been showing a similar trend.
Managing rain-induced disasters
Until a few years ago, the possibility of rainfall deficiency used to be the biggest concern of policymakers during the monsoon season. That is because the potential of drought had serious implications for food security, rural incomes, and overall economy. Over the years, India has become more resilient to rainfall deficiencies, and been able to minimise their impact.
But excessive, localised rainfall, particularly in large, densely populated, urban agglomerations, has emerged as the new headache during the monsoon season, and needs urgent attention. Since the Chennai floods of 2015, a variety of agencies have been working together to reduce the risks of urban flooding in major cities, but the results are yet to be seen. To a large extent, it is an urban planning and municipal governance issue. But its impact is big.
Floods, in general, not just urban flooding, killed nearly 17,500 people in the 10-year period between 2012 and 2021, according to a government statement in response to a question in Rajya Sabha in 2023. The report of the 16th Finance Commission pointed out that floods, again all floods, not just urban flooding, accounted for over 55% of all expenditure on disasters by the states during the five-year period between 2019-20 and 2023-24.
Besides, disruption of cities like Delhi, Mumbai, Bengaluru, or Chennai has very large economic consequences, apart from the direct toll on life and property.
People navigate a street in Kolkata amid heavy monsoon rain in July 2025. Almost every major city in the country has seen at least one major flooding event in the last 10 years, many of them getting classified as disasters. Photo: Express 
Table 1: In the past decade or so, starting with the Kedarnath tragedy in 2013, India has seen at least one major rainfall-related disaster every year.
Table 2: The number of extremely heavy rainfall events has been consistently, and comfortably, above 100 every year since 2017.
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