A feeling of frustration, of being trapped in a crowded place, of becoming internally and externally congested and unable to escape. Whole cultures write about wanting to escape this. Getting off the wheel, depressurizing.

"The root "ah" or "amh" in Sanskrit means press together, choke or throttle. It is curious that this root lives on in many modern languages." [Demonology and Devil-lore by M.C. Conway]
Latin- angi, axi, angor (suffocate, strangle)
Greek- agos (sin)
English - aweful, ugly

"Amhas in Sanskrit means sin, but it does so only because it meant originally throttling — the consciousness of sin being like the grasp of the assassin" [Conway]

The serpent Ahi was conjured by Vritta (the coverer of the sky) to become the great throttler.
Vritta was perhaps a Demon of sorts but most likely, just an asura from a superior tribe.
The Vedic Indo-europeans felt this as a group that caused them to burst out on to the Gangetic Plane. Or so I imagine.