When a factory releases pollutants into a river, the costs of that pollution, contaminated water, harm to fish populations, illness among nearby residents, are typically not paid by the factory itself but by the broader community. Economists refer to such unpriced side effects as externalities. Because the factory does not bear these costs directly, it has little financial incentive to reduce pollution, even though doing so would benefit society as a whole. This mismatch between private cost and social cost is often cited as a primary justification for government intervention, whether through taxes designed to make polluters pay for the damage they cause, regulations that cap allowable emissions, or tradable permit systems that let the market determine the most efficient way to reduce total pollution. Critics of intervention argue that such measures can be costly to enforce and may place developing industries at a disadvantage. Nevertheless, most economists agree that leaving externalities entirely unaddressed tends to produce outcomes that are inefficient for society, even if they are profitable for the individual firm.
Main Idea
What is the main purpose of the passage?