Cities: Skylines II

Pretty self explanatory.
Preparation: I saved a version of my existing city to allow me to earn some achievements without disturbing my main game. You can take out a loan for quick funding if your main game doesn't have enough cash.

Execution: Simply bulldoze any non-renewable energy production buildings* (e.g. coal power plant). Then place lots of wind turbines and connect them to your city's power network. I'm not sure if it's necessary but I removed the power connection to the outside world, so I was entirely self-sufficient on the wind turbines, then the achievement popped.

Note: Some achievements seem bugged or take a few minutes to pop, just enjoy the fresh non-polluted air until they do.

*The game wouldn't let me bulldoze the coal power plant until I bulldozed the powerlines first.