Imagine there is a private factory near your house, and it always emits harmful air - the same air you breathe daily. When a factory produces harmful smoke, it directly costs society. The ‘’free’’ air we breathe daily turns costly because the pollution leads to health problems- medical expenses, hospital visits, lost well-being, and time spent on recovering. This is what economists call a Negative Externality. Because the factory doesn't naturally pay for these harms, governments intervene with per-unit taxes on the factory’s production. This forces the factory to account for those societal costs, ideally reducing pollution or compensating for it.
Market failure happens when the market does not produce the best outcome for society. In a normal market, buyers and sellers interact, prices adjust, and the right amount of goods is produced. But sometimes this balance does not happen. The market may produce too much, too little, or the wrong type of goods. For example, as we said earlier, a factory pollutes the air. The company makes a profit, but people nearby get sick due to the air pollution. The market price does not include this health cost. That’s market failure. Another example is Public goods like street lighting. No one wants to pay for it alone, but everyone benefits. So the market may not provide it at all. In these cases, resources are not used efficiently, and society becomes worse off.
What are the externalitites?
Externalities are costs or benefits created by an economic activity that affect people who are not directly involved in the transaction. In other words, they are spillover effects on third parties. There are two types of externalities: Negative externalities and Positive externalities.
A negative externality occurs when an activity imposes a cost on others. For example, if a factory pollutes a river, people living downstream may suffer from contaminated water, health problems, or reduced fishing income. They bear the cost even though they did not buy the factory’s product.
A positive externality occurs when an activity creates benefits for others. For example, if someone plants flowers that attract bees, nearby farms may benefit from better pollination and higher crop yields. The farmer gains even though they did not pay for the flowers.
Because these external costs or benefits are not included in market prices, markets may produce too many goods with negative externalities and too few goods with positive externalities.