oh really? was it tested near Delhi or Mumbai? We have got a big desert in Raj. Even a tiny country like North Korea exploded a 6 mt device. Get real mate.
Underground nuclear tests did came out after the Tsar Bomba incident. The idea was to minimize the radioactive fall out. So yes, if we have tested a MT device underground, there would not have been any fallout effect just like Shakti tests.
But fallout is not the only case. Underground blast involve one more catastrophic, Seismic effect. So one have to keep in mind the seismic zone of the test site too in mind. Now Pokhran falls in a Zone III which makes it a moderate zone prone to earthquakes.
https://www.mapsofindia.com/maps/india/seismiczone.htm
Now one needs to do a detailed seismographic study of the site and effect of a underground test before going with one. At the time of Shakti, it was not even possible to do that for obvious reason. So the way around was to scale down the yield output and test your design.
@Aaj ka hero ... Castle Bravo test was designed to be a 5 MT device, but the yield came out to be 15 MT. So theoretically that too was a failed test. Now as I said that we had reason for scaling down our design during test. Now if we have not got the desired yield with our scaled down model, it doesn't mean that the design itself was a failure. The original design might have worked perfectly.
As far as HYDROGEN part is concerned, yes, we have tested a BF device instead of a Fusion one in Shakti. But rest assured, we had started working on Fusion design since the later part of last decade.
As far as testing one right now is concerned, One has to be a responsible Nuclear state rather then a Rogue Nuclear state.
