negative externalities
Economics term for costs imposed on third parties not involved in a transaction, such as pollution.
Factory smoke is a typical example of negative externalities.
A carbon tax was introduced to internalize negative externalities.
外部性 is the broader term for externalities, which can be positive or negative. 負の外部性 specifically refers to negative externalities.
正の外部性 is the opposite, meaning positive externalities (benefits to third parties).
Compound of 負 (negative) + の (possessive particle) + 外部性 (externality). 外部性 is a translation of the English economic term 'externality', combining 外部 (outside) and 性 (nature/characteristic).