Let's be honest, there are probably just as many ways to hurt or kill others as there are people to hurt or kill. Some of these ways, while painful, don't last very long — removing the head, for example, is a gruesome but quick way to die. Other ways are a bit slower, and it's pretty much agreed that intentionally dragging out a person's suffering is a crueler thing to do than just ending it on the spot. One particularly painful way of doing things is by suffocating the victim. While this can just be done with Choke Holds, the victims can also be drowned, smothered, hanged, or starved for air in any other way, such as locked in a room with a finite air supply.note The villain will also typically have some evil fun doing it — they wouldn't do it if they didn't get a kick out of watching their victim suffer. If they're particularly cruel, they'll draw it out even longer by giving their victim a few seconds of air in between the suffocating — if they're planning to keep the victim alive, this makes for an effective form of torture. As a matter of fact, the real-life act of waterboarding is controlled drowning. It's just a brutal thing to put someone through, and even if they're intending to leave their victim alive, it's all too easy to go too far and accidentally murder the poor guy.
Of course, villains who cross this line will be portrayed as particularly horrible. Even if they're just a schoolyard bully, putting their victim through this makes them more monstrous and crueler than just being the kid who steals your lunch money — they're someone who'd be fine with outright murdering their victim. Witnesses will be shocked and horrified, and it'll force the hero to work even harder to stop them. If the hero themself engages in this, even as an act of pragmatism, it'll mark them as a dark Anti-Hero at best and someone undergoing a Face–Heel Turn at worst. (Sometimes, though, Super-Toughness or an immense Healing Factor might mean that the windpipe is the villain's only weak point.)
Overlaps with Buried Alive, when the burial is intentional. Another common method is the Vorpal Pillow or being Thrown Out the Airlock. This is one way to end up with Bloodless Carnage, as suffocation victims don't usually end up covered in gore. Can occasionally overlap with Neck Lift or Psychic Strangle. Contrast Comedic Strangling.
No Real Life Examples, Please! While this sort of thing can be common in real-life, especially as a form of torture, we're not going to discuss that here for moral reasons.