The TRAI DND app, on IOS, generates a pre-formatted SMS which is sent to the operator on the standard number 1909.
The Sanchar Sathi app sends it to a DOT entity which then routes it to the operator while updating the govt database of reported spammers and scammers. The options are much extensive than just a spam call/sms.
You can report that the individual was impersonating a public official etc while you can not do than at all with the TRAI DND app.
I suggest you try out the platform on their website first before commenting further.
So the problem was not with the app but with how the information was routed at the back end. The back end of the 1909 system could have been modified to write the data to a central registry as well.
Simply installing Sanchar Sathi won’t eliminate spam calls, which was my point.