Public Goods:Goods or services that are non-rival and non-excludable, meaning their consumption by one person does not reduce their availability to others and it is difficult to prevent people from using them.
Market Failure: A situation where the free market fails to allocate resources efficiently, leading to a net social loss, often due to the presence of externalities, public goods, or information asymmetries.
Pigouvian Tax: A tax levied on a market activity that generates negative externalities, designed to internalize the external costs and align private and social costs.