To get this generation, many states now require fossil fuel powered generators to buy "green tags" from, for instance, solar generators, for every unit of power sold by that fossil plant.

FORBES: Mike Gordon

And most recently, a BBC film crew, 20km away, filmed a cat hunting with the unmistakable matching green ear tags that Bayad-e-Kohsaar was fitted!

BBC: Snow Leopard Diary

When they come back to the ship, they must turn their tags back to green.

NEWYORKER: Stone Mattress

Every time they go ashore, the first one says with a severe Viking frown, they must turn their tags on the tag board from green to red.

NEWYORKER: Stone Mattress