Market failure occurs when there is an inefficient allocation of resources in a free market. Common examples of market failures include the overproduction of cigarettes, underprovision of public goods like education and national defense, and the overuse of SUVs contributing to global warming. Market failures result from external costs and benefits, imperfect information, non-competitive market structures, immobile resources, and inequality. Government intervention is often needed to correct market failures and achieve efficient resource allocation.