Bow and arrow is not a bad idea, actually. Hindus have a mythological attachment to the bow and arrow as Lord Rama's weapon. It's also a projectile weapon, and when shot from a height can do serious damage. It can neutralize these long blades they're carrying. Indian Army promotes professional archery within its ranks, including competitions.
Also, chicoms have a primal fear for mongols with bows and arrows.
Military-grade crossbows don't qualify as "firearms," and can be deployed by India at these ridgelines?