CDSL’s market share has quietly climbed since 2016, and when we started as a depository participant that year, there was a small backstory behind choosing CDSL. 
Quoting @nithin :
We had to choose between NSDL & CDSL. We only went ahead with CDSL because they had a local representative, Harisha, in Bengaluru.
It’s amazing how a small decision can trigger massive change. 