what is major reasons?
The fact that everybody here loves cryptocurrencies, and Bitcoins as major is because everyone in this world likes holding (possessing) what they own, and bitcoin gives them the privilege to hold everything in their hands (and being responsible for anything that happens to it, be it the transactions they send or the fall and rise of values).
Indian Govt is probably not liking it because they are unable to get anything out of this (major reason is due to the fact that everyone tries to get ways to hide their taxes and evade them, so they surely must be doing this through Bitcoins). But all they're speaking about Bitcoins is bullshit, because they really don't understand the power of it. Tell me about a single step that this Government took in Nirav Modi - PNB scam. They're not going to get a fuck from his pockets as the company from which they're going to get some part of his debt collected, had recently declared themselves as bankrupt. They're unable to harm those who're guilty, so they're just trying to push it too hard for the common man itself to even try to make a buck over his invested money.