The Common Kingfisher has 7 regional subspecies over its large range. The UK resident is A. a ispida.
The Southern Indian subspecies, A. a taprobana, is smaller and much brighter blue. (The northern Indian to Southeast Asia subspecies,
A. a bengalensis is also smaller and brighter but is a similar greenish-blue to the nominal and UK.)
These lovely photos of the Southern Indian subspecies are from Dr Harsha Vardhan Reddy.