The Supreme Court of the United States (SCOTUS) recently overruled a previous ruling which has commonly been referred to as "Chevron". At the time this question was posted, there is a summary of the decision on the SCOTUS homepage:
The Administrative Procedure Act requires courts to exercise their independent judgment in deciding whether an agency has acted within its statutory authority, and courts may not defer to an agency interpretation of the law simply because a statute is ambiguous; Chevron U. S. A. Inc. v. Natural Resources Defense Council, Inc., 467 U. S. 837, is overruled.
The full ruling can be viewed here.
Since this ruling has made, I've been seeing a lot of news and commentary that this has a lot of negative consequences, and that it'll make it impossible for federal agencies to actually enforce anything. This may just be because I'm a non-USA citizen living outside of the states though, but I just don't understand why that is, and so I don't understand the source of controversy.
Why has the recent Chevron ruling by SCOTUS generated so much controversy?