Explanation
An externality is a consequence of an economic activity that affects other parties who are not directly involved in the activity. Externalities can be positive or negative, depending on whether they create benefits or costs for others. When a developer builds a new shopping center in a rural area, one externality might be an increase in traffic on adjacent roads. This is a negative externality because it imposes costs on other road users who are not part of the development project, such as increased travel time, fuel consumption, air pollution, noise pollution, and accident risk13. References: LEED v4 Green Associate Candidate Handbook1, Investopedia's Externality