Indian Contract Act, 1872
33. Enforcement of contract contingent
on an event not happening
Contingent contracts to do or not to do anything if an uncertain
future event does not happen, can be enforced when the happening of that event
becomes impossible, and not before.
Illustration
A agrees to pay B a sum of money if a certain ship does not
return. The ship is sunk. The contract can be enforced when the ship sinks.