Flood is a natural hazard that affects the Indian people in a big way. A flood is

A flood is essentially the building up of large quantities of water over land that is normally dry.

An obstruction in water flow may cause a flood but is not itself the flood.

A rise in the groundwater level is a subsurface change, not the surface inundation that defines a flood.

Since the accumulation of excess water clearly defines it, none of the above does not apply.

Heavy rain, dam bursts and overflowing rivers all lead to this excess water on land.

Floods are the most frequent and widespread natural hazard affecting India.