Floods as Chronic Stressors: Rethinking Disaster Health Policy in India

Floods are not only acute disasters but also chronic stressors on public health that deepen existing vulnerabilities in health and social systems. India, with nearly 12% of its landmass flood-prone, faces rising threats from climate change.1 Floods account for major mortality worldwide, yet India bears a disproportionate burden, recording the highest flood-related deaths from 1975 to 2016.2 Yet, in India, disaster relief policy still stops at relief camps, neglecting the silent, long-term crisis that follows. Chronic disease patients, particularly those with limited mobility or financial resources, face disrupted care, medication interruption, and prolonged stress exposure, magnifying mortality risks long after floodwaters recede.3 Thus, we argue that India requires a paradigm shift: from reactive flood relief to a vulnerability–hazard framework that integrates acute and delayed health impacts into public health governance. Evidence from high-income settings, including a recent UK Biobank cohort study, using the Flood Index to estimate flood exposure, showed that floods increase all-cause mortality not only in the weeks after exposure but also after prolonged lags.4 Such work highlights the role of mental health deterioration, disruption of chronic disease care, and cumulative stress pathways. Adapting such methodology to India requires contextualization. Unlike high-income countries, India faces diverse flood types, from riverine to urban drainage failures – each with distinct health pathways. Demography of India is socioeconomically more diverse and young. There is a higher burden of infectious diseases. Data systems differ, and there are major gaps in existing health infrastructure. While no equivalent to the UK Biobank yet exists, methodological elements remain relevant. Retrospective linkage of district-level flood exposure data (Central Water Commission, India meteorological department (IMD), or satellite datasets) with health registries could enable similar analyses. This builds on the existing Ayushman Bharat digital health infrastructure. Using the existing infrastructure, time series models could test for delayed impacts on cause-specific mortality. In the backdrop of existing climate crisis worldwide, it is equally important to shift priorities related to disaster governance. National and state disaster management currently prioritize immediate relief, with health framed primarily through communicable disease control in camps. The silent crises – disrupted dialysis, missed tuberculosis treatment, delayed maternal care, and unaddressed anxiety and depression – rarely enter official reports or compensation schemes. Without institutional mechanisms to capture delayed impacts, these burdens remain invisible. This is where the vulnerability–hazard framework to flood mitigation offers value. Overlaying the Flood Index with IMD’s Normalized Vulnerability Index could spotlight districts where fragile systems and flood hazards collide. The Flood Index by quantifying hydrological hazard and the IMD’s Normalized Vulnerability Index by capturing social disadvantage through indicators such as housing quality, literacy, and health service access can help pinpoint populations where physical hazard and social vulnerability intersect to produce the greatest risk.5 In the context of climate change – projected to increase severe flood frequency and spatial extent by up to 122% by 2100, such integrated approaches become essential.6 Achieving sustainable development goal 11.5 to reduce disaster-related mortality and protect vulnerable populations in India requires more than reactive relief. Studies like the UK Biobank illustrate how integrating flood indices can illuminate hidden, delayed mortality burdens of floods. Yet, its limitations – ecological exposure assignment, selection bias, and lack of healthcare covariates – restrict direct applicability to India. For Indian settings, combining hazard indices with vulnerability measures, ensuring covariate completeness, and using locally tailored retrospective cohort designs could generate actionable evidence. Strengthening data infrastructure to capture both exposure and health outcomes will enable policy to shift from immediate rescue to comprehensive, equity-focused preparedness, aligning disaster response with the realities of a warming world. National programs such as the Digital Health Mission are a step forward toward it. In conclusion, unless India reframes floods as chronic stressors through a vulnerability–hazard lens, disaster governance will continue to miss the invisible, delayed health crises that follow every flood. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.