I thought proliferation laws only apply to nukes and missile tech. Don’t see why subs would be included esp considering both US and Russia plan to sell 5th gen planes which can be considered as strategic as nuke-subs. Unless there’s some law about exporting nuke-powered assets I don’t know about?
It has a reactor fueled with some 20 pounds of plutonium and India is not a participant of nonproliferation agreements so for that reason legally able to sell plutonium to everyone.
For that reason India is a client to avoid for a participant which Russia is.
Also 5-gen aircraft no matter how good it is is not an asset in a class of nuclear sub.