The Environmental Performance Index (EPI) is a method of quantifying and numerically marking the environmental performance of a state's policies, highlighting the degradation of the planet's life-supporting systems on which humanity depends. A world economy that continues to rely heavily on fossil fuels translates into ongoing air and water pollution, acidification of the oceans, and rising concentrations of greenhouse gases in the atmosphere. These changes threaten the survival of species already suffering from widespread habitat loss, pushing them closer to extinction. Recent analyses show that humanity has already transgressed six out of nine critical planetary boundaries that define Earth's safe operating space — and is close to crossing a seventh.