Sikkim

Sikkim is a large state which borders Tibet. A permit is necessary to visit this area. There are four famous caves, these are:

Laringvigphu (Old Cave of God's Hill) in the north, is considered as the most holy and can be reached in three days from Tashiding.
Kadosangphu (Cave of the Fairies) in the south, is at the Reshi hot springs on the Jorethang - Gyalsing highway. It is about ten minutes from the highway across the river Rangit by a pedestrian suspension bridge.
Pephu (Secret Cave) in the east, this is near Sangmoo, which is situated 5 km from Rabongla on the highway between Singtam and Rabongla. One has to walk for half an hour downhill from Sangmoo to reach the cave, which varies in height from 2 to 30 meters. The cave is said to extend beneath both, the Tendong and Maenam hilltops.
Dechhenphu (The Cave of Happiness) in the west, is equally inaccessible and lies near Zongri

The state is part of the Himalya, very mountainous, and consists mostly of gneiss, phyllites and schist. They erode and form poor soils, mostly acidic. The relief and the high precipitation would allow heavy karstification, but there are unfortunately no soluble rocks. The few caves are either artificial or they are of tectonic or erosional origin and quite small. There are neither show caves nor other underground tourist sites.

It is not only the lack of underground sites, also the lack of tourism. The government of Sikkim has extensively promoted tourism in recent years. However, most of it is based on a fledgling gambling industry promoting both casinos and online gambling. Nevertheless, the infrastructure is quite poor and tourism still low.