Natural disaster causing maximum deaths

Ans is 'a' i.e. Hydrological DisasterA "disaster" can be defined as 'any occurrence that causes damage, ecological disruption, loss of human life or deterioration of health and health services on a scale stiffly-lent to warrant an extraordinary response from outside the affected community or area'.* A "hazard" can be defined as any phenomenon that has the potential to cause disruption or damage to people and their environment. - There are many types of disasters such as eahquakes, cyclones, floods, tidal waves, landslides, volcanic eruptions, fires, snowstorms, building collapse, toxicologic accidents, and warfare, etc.* Hydrological disasters (i.e. floods, tsunamis) are associated with causing a maximum death toll. Geological disasters: includes Eahquakes, Avalanches & Volcanic eruptionsMeteorological disasters: include Cyclones, Tornadoes, Hailstorms, Drought, Heatwaves, Blizzards (Blizzards are severe winter storms characterized by low temperature, strong winds, and heavy snow).