Contract becomes impossible of performance if:

Under Section 56 of the Indian Contract Act, a contract becomes void if its subject matter is destroyed at the time of contract formation (initial impossibility). This is known as 'agreement to do impossible act.' Mere unavailability of goods, worker strikes, or lack of money are commercial risks that don't make performance impossible - they may constitute breach but don't void the contract ab initio. Destruction of the subject matter before formation is the only scenario that makes the contract void from the beginning.