The distance between Bum La pass and nearest division HQ (Bomdilla, elevation 2217m ) is 226 km by road, less than hour's flight aboard a CH-47F.
The distance between Gurudongmar and nearest division HQ (Gangtok, elevation 1650m ) is 175 km by road, less than an hour's flight aboard a CH-47F.
For all that is being said and done in the last 2-3 pages, M777 is light howitzer capable of being airlifted.
It is not the defacto mode of transportation.
As for the airdrop, you are deliberately and falsely creating a mental picture of this
when the reality is
Also Pakis airlifted their 105s in pieces by dismantling at Skardu and reassembling in the field. IAF airlifted LFGs during Kargil by Mi-8/17 without dismantling.