Humans are evil, we create different products such as the CFCs that eventually harm the environment such as the ozone layer causing it to deplete. One of the way to combat against the depletion of the ozone layer is to issue a worldwide ban on the production of CFCs and find another replacement for it which we had and hence the ozone layer is recovering steadily over the years. It shows how we have to constantly monitor the causal and effect of our actions and its impact on the environment and not assume that nature will reach its equilibrium and recover. Immediate actions have to be taken to ensure the world is sustainable.