Why in news?
Communities in Meghalaya are exploring responsible cave tourism as a way to protect underground landscapes and support local livelihoods. A November 2026 report by Mongabay India describes these efforts around caves including Mawmluh, near Sohra, also known as Cherrapunji. The report places them against pressures from mining and changing rainfall. Mawmluh has particular scientific value: a mineral formation from the cave provides an international reference point for a division of geological time. Protecting the cave therefore helps preserve both a living underground environment and evidence of past climate.
Where Mawmluh lies
Mawmluh Cave is in East Khasi Hills district, Meghalaya, in northeastern India. Meghalaya lies south of the Brahmaputra valley and has a long border with Bangladesh. Sohra sits in the southern part of the Khasi Hills, above the plains to the south.
The International Union of Geological Sciences describes Mawmluh as a cave system about 7.2 kilometres long, with several openings. It developed along the contact between the Lakadong dolomite of the Sylhet Limestone Formation and the Therria Sandstone Formation. Its passages contain hanging mineral formations, rising formations, columns and curtain-like deposits.
How water shapes a cave
In limestone landscapes, rainwater can absorb carbon dioxide from the air and soil. This makes the water mildly acidic. As the water passes through cracks, it dissolves carbonate rock and gradually enlarges underground openings. Such landscapes are called karst. The movement of water connects the ground above with the passages below.
Water can also build formations inside an existing cave. Dripping water carries dissolved minerals. When conditions allow calcium carbonate to come out of solution, a thin deposit remains. Repeated deposits produce speleothems, the collective name for these cave mineral formations. Stalactites hang from the roof; stalagmites rise from the floor. A column can form when the two meet.
A mineral record of the monsoon
Successive mineral layers can preserve changes in the water from which they formed. Scientists date the layers and examine their chemical composition. Oxygen isotopes are forms of oxygen with different masses. Changes in their relative abundance can help researchers reconstruct earlier rainfall and monsoon conditions, using the relationship between the cave record and the surrounding climate system.
A stalagmite from Mawmluh, known as KM-A, contains an important record of a weakened monsoon around 4,200 years before 1950. Researchers used uranium-series dating to establish the timing. The record gives scientists evidence from a period long before modern weather measurements.
Why the name Meghalayan is international
In 2018, the International Union of Geological Sciences ratified three formal subdivisions of the Holocene Epoch: Greenlandian, Northgrippian and Meghalayan. The Meghalayan is the latest of these subdivisions. Its beginning is defined at a specified level in the Mawmluh stalagmite.
This reference is a Global Boundary Stratotype Section and Point, or GSSP. A GSSP gives geologists an agreed physical reference for a boundary in the geological time scale. They can use it when comparing records from different places. The KM-A sample is kept at the Birbal Sahni Institute of Palaeosciences in Lucknow.
Conservation and local livelihoods
Mongabay's report describes local interest in community-managed tourism that helps visitors understand caves. It also records expert calls for scientific monitoring, stronger protection around cave systems and benefits for local residents. These proposals connect conservation with the choices available to communities living near the caves.
The cave's dependence on water also explains why protection has to consider the surrounding landscape. Water enters through the rock above and moves through underground passages. Changes to that setting can affect the conditions inside. Guided access, careful management and cooperation between residents and researchers can support the conservation of these sensitive places.
Conclusion
Mawmluh connects Meghalaya's local landscape with the international geological time scale. Its scientific value lies in the mineral record it preserves. Community participation can help keep that record and the wider cave environment part of a lasting local conservation effort.
Sources
- Mongabay India, 10 November 2026: community approaches to cave conservation
- International Union of Geological Sciences: Mawmluh location, geology and reference sample
- International Commission on Stratigraphy: formal Holocene subdivisions and Mawmluh GSSP
- US Geological Survey: limestone dissolution and cave formation
- US Geological Survey: stalactites, stalagmites and mineral deposition
- US Geological Survey: water and carbonate cave deposits