The freezing caves on an isolated stretch on the Leh-Manali route, 4,000m above sea level, look anything but hospitable. The path is treacherous, cutting through mountains, but part of one that connected ancient India to China and Central Asia — the Silk Route. That traders, travellers and pilgrims took this route has been known for years.
What isn’t known is how they survived it. A study by geochemists from the Birbal Sahni Institute of Palaeosciences in Lucknow may have found the answer — in a maze of interconnected caves beyond the last pass before Leh, near the Rumtse, Sasoma, Sumdo, Gya and Meru villages in the Ladakh valley. Scattered across these caves, about eight-12 feet high and 10 feet wide, are traces of life — broken pottery, diyas and, the key to their findings, soot.
“It seems the caves have been in use since before the 11th century,” Dr Anupam Sharma, lead author of the paper published in the ‘Journal of Archaeological Science: Reports’ by Elsevier, told TOI. “The caves were used intermittently by travellers and transhumant communities (those who move with livestock seasonally to look for summer and winter pastures), mostly in summer. But they could have been in use throughout the year.”
Ladakh had been the convergence point between central and south Asia when the Silk Route was thriving. “The 60-day journey on the Ladakh route linking Amritsar (Northwest India) and Yarkand (Southwest China) on the Silk Route (southern branch) was employed by merchants until the late 18th– 19th century when mainland borders between India and China were closed for strategic reasons,” the paper said.
Co-author Dr Amritpal Singh Chaddha said, “The Himalayan economy was dependent upon its trade with central Asia and China.” Evidence of human presence in these areas is not new. But winters are excruciatingly long and the mountains remain snow-covered for three to four months. The air is thin, there is barely any rain and vegetation is restricted to the valleys alone. “We found soot on the roof of the caves. These go back to the 17th-18th century… It is believed that it is the last known date up to which the caves were used by humans,” Sharma said.
The Ladakh samples suggest wood was burnt inside these caves, depositing a hard, sticky, shiny, and resinous black charred material on the roof. “Such coatings may be the result of a condensed smoke generated by fire based activities (cooking and heating), most likely to maintain habitable conditions inside the caves,” the paper said. “Additionally, the use of oil for lighting torches also supports the formation of smoke.”
Sharma said the presence of “the nearby Stupa and Mane (small Buddhist structures) suggest the caves may have been also used for religious purposes.” With time, the concentrated pollutants inside the caves may have thrown them into disuse. Pneumoconiosis, lung diseases caused by dust inhalation, is prevalent across Ladakh. And with its emergence two centuries ago, people stopped using thee caves as stopgap shelters.