The smell of tripe cooking is truly gag-worthy.... I wish I had a barfing emoji.
Any kind of disgusting smell... If I had to choose one, I'd choose the smell from a sewer
Rotting meat. Yuck!
bad cat litter that needs to be cleaned.
While all these ⬆⬆⬆⬆🙊 other answers are very ummmm appropriate to say... I'm gonna add something that was a first for me recently.... A ran over skunk in the middle of the road and no one wanting/willing to pick it up for a few days! (Shudders) you can still smell the spot driving by even though the body is gone now!Â
Oh and boiling/cooking ribs! YUCKETH!!!
I agree with the observations about sewage. But oddly the smell that most makes me want to barf is that overpowering sickly sweet faux "perfume" that hits you when you enter a garden centre or similar and they are selling those Yankee candle things. I now avoid shopping at two such local centres. How's that for sales prevention?
The paper mill.
Artificial Raspberry flavoring in anything.
Wet dog. It's nauseating.