Not a lot the Indians can do about it.
If the Indians really want this to stop, they should go on full military alert and flood massive numbers of troops to the region while readying all strategic weapons. It then looks like a massive overreaction and runaway escalation. The Chinese are doing this because they think they can without any consequences. India isn’t the pushover it once was. They have real weapons today. Could they beat the Chinese in an all-out conventional war? No. But the Chinese would take major blows from such a conflict making it completely not worth whatever they may gain. And if it went nuclear? Even worse for everyone involved.
The Chinese aren’t stupid; they’d back down. You just have to convince them you’re crazy enough to go all-in.