Central Government Act
Section 21 in The Indian Contract Act, 1872
21. Effect of mistakes as to law.- A contract is not voidable because it was caused by a mistake as to any law in force in 1[ India]; but a mistake as to a law not in force in 1[ India] has the same effect as a mistake of fact. 2[ Illustration A and B make a contract grounded on the erroneous belief that a particular debt is barred by the Indian Law of Limitation: the contract is not voidable.