Section 33 in The Indian Contract Act, 1872
Title: Enforcement of contracts 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.
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.
Title: When event on which contract is contingent to be deemed impossible, if it is the future conduct of a living person.
If the future event on which a contract is contingent is the way in which a person will act at an unspecified time, the event shall be considered to become impossible when such person does anything which renders it impossible that he should so act within any definite time, or otherwise than under further contingencies.
A agrees to pay B a sum of money if B marries C. C marries D. The marriage of B to C must now be considered impossible, although it is possible that D may die and that C may afterwards marry B.
Title: When contracts become void which are contingent on happening of specified event within fixed time . When contracts may be enforced, which are contingent on specified event not happening within fixed time.
Contingent contracts to do or not to do anything if a specified uncertain event happens within a fixed time become void if, at the expiration of the time fixed, such event has not happened, or if, before the time fixed, such event becomes impossible.
When contracts may be enforced, which are contingent on specified event not happening within fixed time.—Contingent contracts to do or not to do anything, if a specified uncertain event does not happen within a fixed time may be enforced by law when the time fixed has expired and such event has not happened or, before the time fixed has expired, if it becomes certain that such event will not happen.
(a) A promises to pay B a sum of money if a certain ship returns within a year. The contract may be enforced if the ship returns within the year, and becomes void if the ship is burnt within the year.
(b) A promises to pay B a sum of money if a certain ship does not return within a year. The contract may be enforced if the ship does not return within the year, or is burnt within the year.
Title: Agreement contingent on impossible events void.
Contingent agreements to do or not to do anything, if an impossible event happens, are void, whether the impossibility of the event is known or not to the parties to the agreement at the time when it is made.
(a) A agrees to pay B 1,000 rupees if two straight lines should enclose a space. The agreement is void.
(b) A agrees to pay B 1,000 rupees if B will marry A's daughter C. C was dead at the time of the agreement. The agreement is void.
Title: Obligation of parties to contracts.
The parties to a contract must either perform, or offer to perform, their respective promises, unless such performance is dispensed with or excused under the provisions of this Act, or of any other law.
Promises bind the representatives of the promisors in case of the death of such promisors before performance, unless a contrary intention appears from the contract.
(a) A promises to deliver goods to B on a certain day on payment of Rs. 1,000. A dies before that day. A's representatives are bound to deliver the goods to B, and B is bound to pay the Rs. 1,000 to A's representatives.
(b) A promises to paint a picture for B by a certain day, at a certain price. A dies before the day. The contract cannot be enforced either by A's representatives or by B.