A non-rival and non-excludable good is referred to as a public good. Nonrival means that one person's consumption has no effect on the consumption of another. Non-excludable, on the other hand, implies that no individual can be barred from using the good. Parks, roads, national defense, government administration, and so on are examples of services that cannot be provided by a market mechanism. These items are required for survival and national development.
The government must provide these goods for the following reasons:
i. The benefits of public goods are easily accessible to anyone without affecting the consumption of others. There arises a failure of the market.
ii. As public commodities are open to everyone, no one can be denied access to them. When the relationship between the producer and the consumer breaks down, the government is forced to intervene through public policies.