Speeding up index deletion

Elastic Stack Elasticsearch
1

Prior research (that didn't help): Slow Index Deletion
ES version: 2.4.0
Number of nodes: 6
_cat/indices: green open ABC 8 1 46191901 165 200.9gb 100.3gb

In ES logs, I see a line like:

cluster state update task [delete-index [ABC]] took 35.7s above the warn threshold of 30s

Why does deleting the index take this long? How can I make it faster?

Thanks!

2

It could be many things, such as slow disk.
Is it causing problems? Howe are you measuring the load on the system?