US government often gives their estimates out. You can find them on cia.gov and various defense related sites. If this isn't the US government, I don't know who is
And Harvard has no credentials in nuke research. Your Indian lobbyists gave a bigger check to the wrong person. He should've done it to a proper institute that would've been credible. Unless these 2400 additional weapons came from the Vedic times, they don't exist as you don't have that much raw material and capability to make these many weapons in a few years!