A couple of kilometres before the Bangladesh border, near the village of Nongjri in Meghalaya, a small cemented path heads through areca nut plantations and an evergreen forest. It ends at a rocky outcrop, which is the opening to the Krem Lymput, a six-kilometre long limestone cave nestled in the East Khasi Hills. About two months ago, I was in Shillong—the capital of Meghalaya—and after four days of waiting for an Arunachal Pradesh permit, I was weary of the crowds and tired of the March sun. After trawling a few pages online that sold me the root bridges of Sohra in Meghalaya, I chanced across the possibility of disappearing into the earth in the Khasi hills. The descent into the krem—khasi for cave—is the beginning of an adventure involving jagged low ceilings, slippery inclines, belly-crawling, and wading through crystal pools of water. The thrill of it lies in the discovery of absolute darkness and silence hosting endemic species—such as bats, fish, insects and arachnids—fossil passages, and fantastically shaped stalactites and stalagmites that slowly formed over thousands of years.

The belt of the Khasi, Garo and Jaintia Hills, which is around 200 kilometres long and 30 kilometres wide has more than a thousand cave systems that date back to the Eocene Epoch—a division of the geologic timescale from 56 to 34 million years ago. While local populations have known about these caves for generations, the Meghalaya Adventurers Association (MAA), which was founded in 1990, began the process of formal documentation only in 1992.

Brian Kharpran Daly, a founder member and general secretary of the MAA, told me when we spoke on the phone, “When we started, we never had equipment, it was all crudely put together. We realised we do not have the expertise so we reached out to international cavers.” This process that started in 1992, turned into an annual collaborative project of speleologists from several countries—under the banner of the Abode of the Clouds Expedition—which Kharpran said has documented 1350 caves and mapped 387 kilometres of cave systems till date. In a podcast for the multi-language news platform swissinfo.ch on 11 April 2015 , Swiss caver and an expedition member of the "Abode of the Clouds", Thomas Arbenz said, “You go there and you are the first to set foot on a new, empty blackness … like explorers in old days. [There are] 30–40 new caves, 20 kilometres of cave passages in one expedition.”

“Whether big or small, a cave is thrilling to discover. It is a different experience to delve into the dark territory,” said Kharpran. No wonder then that spelunking or caving has been growing in Meghalaya as a niche adventure sport in recent years. Piran Elavia a former IT professional who has been exploring these caves since 2010. Realising the potential of the sport, he started offering cave expedition tours through his eco-tourism company Kipepeo in the same year. “I started out with a group of seven people in the first year, and now there are at least 50–60 people per season,” he told me when we talked last month.