[…] a situation in which individual users, who have open access to a resource unhampered by shared social structures or formal rules that govern access and use, act independently according to their own self-interest and, contrary to the common good of all users, cause depletion of the resource through their uncoordinated action.

(“Tragedy of the Commons” 2022)

Related: Prisoner’s Dilemma.

References

“Tragedy of the Commons.” 2022. Wikipedia, March. https://en.wikipedia.org/w/index.php?title=Tragedy_of_the_commons&oldid=1076616212.