Every year on October 13, the United Nations marks the International Day for Disaster Risk Reduction, a date the General Assembly fixed in 2009 after first setting aside a day for natural disaster reduction in 1989. The aim remains the same: to communicate the urgency of disaster resilience at all levels, from farmers and fisherman to first-responders, to policymakers.

Since the Sendai Framework 2015, the day has also stressed local capacity development, community participation, and the developing climate and disaster resilience.

That second concern puts infrastructure at the center of the conversation, because roads, power lines, water systems and homes are what disasters damage first and what communities spend years rebuilding.

As per the latest UNDDR (United Nations Office for Disaster Risk Reduction) report, direct asset damage by disasters costs $202 billion annually, while cascading damages including ecosphere destruction, supply chain breakdowns, and insurance surpass $2 trillion each year.

Over a 50-year period (1970–2021), weather, climate, and water hazards generated a staggering $4.3 trillion in economic losses globally. The toll in India has been colossal too.

Cyclone Amphan, which struck West Bengal and Odisha in 2020, killed 98 people and caused $13.5 billion in damage. Satellites tracked the storm across the Bay of Bengal, yet the damage was decided on land, where its winds tore roofs off houses. Geospatial is a non-negotiable for disaster-resilient infra anywhere across the globe.

This year’s UN theme, “Resilience Starts at Home,” carries the same argument down to the household, and UNDRR puts it plainly by saying that no one should have to choose between an affordable home and a safe one. It was also the question before the National Colloquium on Disaster Risk Reduction, held on 13 October at Suhora Technologies and organised by the IEEE Local Group – Data Science for Climate Risk Management, which Geospatial World attended. One speaker was direct about where plans succeed or fail.

“No DRR&R plan, policy, guideline, strategy or framework can be fully successful if it does not involve communities and households for grassroot level acceptance, adaptation, action and practice into regular life style and lives, livelihood in living places of people,” said Prof. Surya Parkash Gupta, Founder Chairperson, Community Based Disaster Risk Management Society, India.

Where the Risk Is Mapped

Prof. Gupta’s presentation went on to show why households matter so much in India, noting that 85% of the country’s land area is vulnerable to natural hazards, that 65% is prone to earthquakes, 12% to floods and 8% to cyclones, and that 70% of cultivable land is prone to drought. He reiterated that the first 24 to 72 hours after a major disaster depend almost entirely on the people nearby, since formal responders have not yet arrived.

Figures like these rest on maps of hazard and exposure, and satellites keep those maps current by showing where land is steep, where rivers spread and where homes are crowding into both.

ISRO’s Landslide Atlas of India, published in 2023, shows how this works, using remote sensing data to map and monitor landslides. The same view matters for housing, because the Midterm Review of the Sendai Framework, cited in the presentation, found that many countries still struggle to enforce land-use and building rules in hazard-prone areas and to bring households into decisions about risk.

Informal settlements are often left out of planning altogether, and the effects of a disaster fall hardest on women, children, older people, people with disabilities and low-income families. Fine-scale imagery that shows where such neighbourhoods have grown gives planners a way to bring them back into view.

A Collective Duty

The presentation described the responsibility as shared, with governments enforcing planning rules and building codes, developers and insurers telling buyers about known hazards, and households learning their local risks and keeping a plan and 72 hours of water and food. Early warning is where these duties meet.

The UN’s Early Warnings for All initiative, launched in 2022, aims to protect everyone on Earth from hazardous weather, water or climate events by the end of 2027, and two of its four pillars, risk knowledge led by UNDRR and observation and forecasting led by the World Meteorological Organization, draw directly on satellite and ground observations.

The pressure on all of this is rising. The Centre for Science and Environment recorded extreme weather events in India on 331 of the first 334 days of 2025, up from 295 days in 2024, with at least 4,419 deaths, 181,459 houses destroyed and 17.4 million hectares of cropped area affected, and it noted that gaps in reporting mean the true figures are higher. Against numbers like these, one speaker at the colloquium argued that the answer has to start with habit.

“With climate change impact, frequency of disasters will increase manifold in coming years. To mitigate the impact of any disaster, culture of preparedness should be ‘Mantra’ at national, state, district, family and individual level. Culture starts from home. Resilience is not only safe building but individual actions. Let us work together with national and state government to meet the goals of Sendai Framework,” emphasised Prof. VK Sharma, Vice Chairman, Sikkim State Disaster Management Authority.

The Water Risk

Water adds another layer, and it begins with the events everyone can see. River floods, flash floods and dam-related emergencies threaten lives, infrastructure, farms and ecosystems, and Dr. Dipankar Saha, Chair Professor, MRIIRS, and Board President, Water For People India, noted that human choices are making such events more frequent.

Unplanned building and widening of roads in fragile hills such as the Himalayas, he said, triggers landslides, and he stressed that every disaster other than earthquakes and volcanic activity is linked, directly or indirectly, to human-induced climate change.

The quieter danger sits underground, where depletion, contamination and the movement of seawater into coastal aquifers unfold slowly and with no single event to mark them.

Satellites have already shown the scale in the north of India, where NASA’s GRACE mission found that more than 109 cubic kilometres of groundwater disappeared from aquifers between 2002 and 2008. Dr. Saha stated that the country’s dependence on groundwater turns any damage to it into a problem for millions, and he put that dependence in numbers.

“People are less aware of groundwater-related disasters as they invade in a slow process and silently, like depletion of resources, contamination of sources, seawater intrusion invading freshwater coastal aquifers, and land subsidence”, noted Dr. Saha.

“Any impact on groundwater puts millions in trouble, as 85% of rural drinking water needs and 62% of irrigation requirements in India are catered to by groundwater, besides supplying more than 50% of urban water needs,” he added.

What Space and Geospatial Adds

The clearest contribution comes during a disaster, when the first need is to see what has happened across a large area while cloud, rain and damaged roads block the view from the ground. Radar satellites solve part of this, since they see through cloud and work day or night.

During the 2022 monsoon, ISRO’s National Remote Sensing Centre(NRSC) combined radar data from Sentinel-1A, RISAT-1A, Radarsat-2 and ALOS-2 PALSAR with optical imagery to follow floods in Uttar Pradesh, producing 36 flood inundation maps between 9 August and 26 October that together showed 639,061 hectares under water, and it published the results on the National Database for Emergency Management and the Bhuvan geoportal.

The same logic works across borders through the International Charter Space and Major Disasters, in which 17 space agencies share imagery with emergency responders at no charge. By January 2025 the Charter had imaged 943 disasters in 136 countries, and in 90% of its 2023 activations the first image of the affected area arrived within two hours.

The larger gain comes before the event, because risk is cheaper to reduce than to repair. Elevation models, land-use layers and building footprints let planners see which slopes, riverbanks and coastal strips are unsafe to build on, and images taken...

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