Natural Hazard Zones of India: Earthquakes, Floods, Droughts and Cyclones

Why Does a Hazard Become a Disaster in One Place and Not Another?

• Hazard: a natural process that can harm people, property or the environment. On its own, it is not yet a disaster.
• Exposure: people and assets that sit where a hazard may strike. Coastal villages in Odisha, for instance, are exposed to Bay of Bengal cyclones.
• Vulnerability: conditions that leave exposed people or assets unable to cope. Unreinforced brick houses in Gujarat were vulnerable to strong shaking in 2001.
• Putting it together: the 2001 Bhuj earthquake killed thousands and destroyed homes across Kutch. A hazard turns into a disaster only when exposure and vulnerability are both present.

What Do India’s Four Seismic Zones Actually Mean?

• The standard: India’s current seismic design standard is IS 1893 (Part 1):2016. It divides the country into seismic Zones II, III, IV and V, each meaning a similar level of expected ground shaking.
• Zone V, the highest risk: it covers parts of the Northeast, Kutch in Gujarat, and the Andaman Islands. In June 2026, Parliament flagged the Kangra-Chamba-Dharamshala belt in Himachal Pradesh, also Zone V, for recording 16 earthquakes that month.
• A proposal that didn’t survive: in November 2025, BIS floated a new, even higher-risk seismic zone. By March 2026 it was withdrawn, reverting to the existing four-zone 2016 code, over construction-cost concerns.
• What maps can and can’t do: earthquake maps guide planning and building rules, but they cannot predict an earthquake, and they cannot guarantee any one site is safe from local ground effects.

Why Does the Bay of Bengal Get So Many More Cyclones Than the Arabian Sea?

Tropical cyclones form over both the Bay of Bengal and the Arabian Sea, but the two coasts don’t share the risk equally.

• Two basins: the Bay of Bengal produces roughly four times as many cyclones as the Arabian Sea. More than 60% of Bay of Bengal cyclones strike India’s east coast.
• The Arabian Sea side: Gujarat is especially exposed to the cyclones that do form there and make landfall.
• Storm surge: an unusual rise of sea level near the coast during a cyclone. The 1999 Odisha super cyclone caused a storm surge that flooded coastal districts.
• A living reference, not a boundary: IMD publishes a cyclone-prone district list as a planning reference. It is not a fixed line on a map.

How Does India Watch for the Next Tsunami?

• What a tsunami is: a series of long ocean waves, usually triggered by undersea earthquakes. In deep water it has a long wavelength and small height; near the coast it slows, compresses, and rises sharply.
• 2004, the turning point: the Indian Ocean tsunami struck Tamil Nadu and the Andaman Islands, and exposed how unprepared the region was.
• INCOIS: the Indian National Centre for Ocean Information Services was established on 3 February 1999. It has run India’s 24-hour tsunami warning centre since October 2007, set up in direct response to the 2004 disaster.
• What the centre does: it monitors undersea earthquakes and issues coastal advisories, part of the wider SACHET early-warning system that also draws on IMD, CWC, GSI and DGRE data.

Is India’s Famous 40-Million-Hectare Flood Figure Still Accurate Today?

• The 1980 estimate: the National Commission on Floods (Rashtriya Barh Ayog) estimated about 40 million hectares as flood-prone, back in 1980. That figure is a historical estimate, not a precise current map.
• Why it keeps shifting: flood risk changes with embankments, land use and river management over time. Assam, West Bengal and Bihar remain among India’s most flood-prone states today.
• Four kinds of drought: meteorological drought means less rain. Agricultural drought dries crop soil. Hydrological drought lowers river or reservoir levels. Ecological drought harms habitats.
• Where it bites hardest: drought risk is higher in areas with low or uneven rainfall, especially parts of western India and the peninsular interior. The National Institute of Disaster Management publishes a dedicated manual on drought management.

How Much of India Actually Sits on Landslide-Vulnerable Ground?

• The scale: about 420,000 square kilometres of hilly terrain is landslide-vulnerable, spanning parts of 19 States and Union Territories.
• Where it happens: landslide-prone belts include the Himalaya, the Northeast hills, the Western Ghats, the Nilgiris, and the Konkan coast.
• Why prediction is hard: landslides depend on local slope, land use and vegetation, so regional prediction is difficult even with good maps.
• A global response: in 1994 the United Nations adopted the Yokohama Strategy for disaster reduction. It followed the UN’s declared International Decade for Natural Disaster Reduction, 1990 to 2000.