Why do a lot of asian people from Pakistan/India have interestingly coloured eyes?

I’m south asian myself and have the regulation deep brown eyes, not complaining, but some asian friends I have that come from India/Pakistan have green/blue/grey/light hazel eyes and with their skin tone they look, just, amazing! Kind of ethereal for all of them, (but especially in the case of the men, i cannot stop staring!)
It is simply beautiful (have to admit i’m jealous) :)
But I noticed every asian person i know/have met with these sort of eyes have come from pakistan in some way.

just anyone know why a) a lot of them have light coloured/unusual coloured eyes

b) are fairly light in their skin tone, but asian. (they look like an asian/caucasian mix, but they aren’t? sorry doing my best to describe what i mean! haha)

this is an odd question but i am curious as to the genetics/geography of the whole thing being a biology/science student in general.
(am thinking of studying this for my extended project in july)

my parents come from sri lanka, and people with non-brown eyes are VERY rare, as are very light-skinned asians there. but when i have visited pakistan, i notice them a lot.

any insight you can give me would be good.
throw some sciencey shit about alleles and pheno/genotypes in there if ya like! i dont mind :)