Section 30 in The Indian Contract Act, 1872
Title: Agreements by way of wager, void.
Agreements by way of wager are void; and no suit shall be brought for recovering anything alleged to be won on any wager, or entrusted to any person to abide the result of any game or other uncertain event on which any wager is made.
Exception in favour of certain prizes for horse-racing.—This section shall not be deemed to render unlawful a subscription or contribution, or agreement to subscribe or contribute, made or entered into for or toward any plate, prize or sum of money, of the value or amount of five hundred rupees or upwards, to be awarded to the winner or winners of any horse-race.
Section 294A of the Indian Penal Code not affected.—Nothing in this section shall be deemed to legalize any transaction connected with horse-racing, to which the provisions of section 294A of the Indian Penal Code (45 of 1860) apply.
Title: "Contingent contract" defined.
A "contingent contract is a contract to do or not to do something, if some event, collateral to such contract, does or does not happen.
A contracts to pay B Rs. 10,000 if Bs house is burnt. This is a contingent contract.
Title: Enforcement of contracts contingent on an event happening.
Contingent contracts to do or not to do anything if an uncertain future event happens cannot be enforced by law unless and until that event has happened.
If the event becomes impossible, such contracts become void.
(a) A makes a contract with B to buy Bs horse if A survives C. This contract cannot be enforced by law unless and until C dies in A's lifetime.
(b) A makes a contract with B to sell a horse to B at a specified price, if C, to whom the horse has been offered, refuses to buy him. The contract cannot be enforced by law unless and until C refuses to buy the horse.
(c) A contracts to pay B a sum of money when B marries C. C dies without being married to B. The contract becomes void.
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.