Aerosolised oil
The microscopic oil droplets thrown into the air by high-heat Indian cooking — tadka, deep-frying, dry-roasting. They drift, settle as a sticky film on every surface they reach, and carry smell with them. The real reason an open Indian kitchen misbehaves — it's not smoke, it's oil.
Why open kitchens misbehave
Boiling and steaming release steam, which disperses. Tadka and frying release aerosolised oil, which sticks — which is why cooking style, not taste, decides the kitchen boundary.