I saw this species commonly in Kolkata and elsewhere, as well (I think)
as its close relative the mottled emigrant, Catopsilia pyranthe.
In fact, I think it was the first butterfly I saw, fequenting avenues
of trees in the centre of the city. But despite being common it was
very mobile and hard to photograph - the picture above is the only half
decent picture I got.
Fred had similar difficulties with the species, but got this single
My butterfly is the pale
yellow-white of a male while his is the deeper yellow of a female.