In March, 2019, we spent almost two weeks on a photographic tour around Sri Lanka. Whilst this was not specifically targetting odonata, I did take every opportunity to look for them when and where I could. I notched up 22 species, 10 of which were “lifers”, so I was quite content.
Sri Lanka has a rich population of odonata with 129 species recorded, 49 of which [I believe] are endemic, so it is certainly worth further investigation.
Below is a Google Map of the species I found at various sites. The numbers in the flags indicate the Species count at each site.