Comment by LimaBearz

Basically, food.

Your nutrition changes your smell. You usually do not consciously notice except for very strong smells like from garlic or asparagus consumption. But a lot of food has this effect, and in sum the effect of the things one typically eats lead to a typical smell. Since nutrition is often culturally determined, different cultures smell differently. You just don't smell your own, because you get used to it.

Just to fit in the missing piece of the puzzle: In the UK (and unlike the US), the term “Asian” is frequently associated with Indian and Pakistani and not just East Asians.

I’m guessing this is what the OP had in mind.

Blurting this out must have been mortifying.