The status quo in most places is : pretty much people pollute however they want at zero marginal cost to themselves, without needing any credits, and passing on

The status quo in most places is : pretty much people pollute however they want at zero marginal cost to themselves, without needing any credits, and passing on the costs to the environment as a whole. The credits are an improvement, because polluters at least have to pay for pollution credits, which means they have an incentive to pollute less.