Ans. Sometimes, a Legislature may enact a law which is apparently within its authority and scope but in substance it violates its constitutional jurisdiction. In such legislation, the outer form of law is not important whereas its substance should be considered. Such legislation or law is called colourable legislation. When the question of the validity of such law arises before the courts, they apply the doctrine of colourable legislation and declare the law as invalid. For example. the Bihar Land Reforms Act, 1950 was challenged before the Supreme Court on the ground of colourable legislation and the court, in Kameshwar Singh Vs. State of Bihar, declared that the law in question is invalid.