Cool! We are back to attributing motives such as "sinister". Reminds me of what someone keeps telling me:
Do not attribute to malice, that which is perfectly attributable to stupidity
(just a general comment, nothing about any particular view being stupid - except the demand to "test" for the heck of it)
To me, the deterrence issues are:
1) Does India possess nuclear weapons? i.e., things that CAN
cause instant, massive destruction?
2) Does India have systems deployed to deliver these a) with rapid response, b) survivability to pre-emptive surprise attack c) reliably and d) accurately enough to hit within the CEP of the weapons?
3) Does India have the command and control structure to ensure swift and certain response that survives a decapitation strike on its political and military leadership?
4) Does India have the WILL to ensure swift and massive response?
If all 4 are "YES", then I ain't messing with India. Better to go invade or terrorize Antarctica or Nauru or some place like that instead. IED-Mubarak a couple of glacier overhangs - they make spectacular pictures in National Geographic along with the nekkid wimmen pictures.
Item 1) here is a "CAN" not a "WILL". Because I am NOT
going to bet on the warhead not exploding, or of only burning me to a nice lump of carbon, instead of 99.97% gaseous state CO2 + H2O that glows in the upper atmosphere. That's as stupid as playing cricket with a hand grenade, and there's nothing to prevent India from over-compensating for a 50% fizzle probability by dumping 6 warhead on me.
So the argument for LIVE NUCLEAR TESTS beyond the ones in 1998 is completely bogus. Not sinister, just stupid. Item 1 is demonstrated. Period. Move on to the bigger things.
Items 2 through 4 can be refined very substantially, and the very fact that there is effort to refine these continually is very deterring. It shows that there is real thinking behind these issues, and that scares the heck out of me as a potential invader. So it is real deterrence.
Every refinement in Items 2 through 4 by India vastly increases the cost to the adversary to try to counter that, so the deterrence value is much greater. "More data on weapon yield" is by far the lowest priority.
Items 2 and 3 involve large improvements in the economy, distributed throughout the country. Robust power systems, transport systems, emergency response systems, food growth, manufacturing capability, options for massive resistance even if all the tanks and fighter bases are knocked out.
Item 4 is somewhat inversely related to economic development, but with good public threat awareness, which means good communication to counter the propagandoos, the public will maintain a sense of outrage that will ensure the will to go to all-out war against any enemy that inflicts massive damage. Massive damage is easier to empathize for the population if they see well-dressed aadmi-aurat lying dead and wounded, and nice makaans damaged or destroyed, than by images of poor Kashmiri or Northeastern citizens killed.
So beyond a basic level, economic development in the hinterlands of India INCREASES the empathy of the elite in the cities, and kindles some slight realization that the same could happen to them if they don't get off their musharrafs and hit back at the enemy.