EDITOR'S NOTE: Call to Earth is a CNN editorial series committed to reporting on the environmental challenges facing our planet, together with the solutions. Rolex's Perpetual Planet Initiative has partnered with CNN to drive awareness and education around key sustainability issues and to inspire positive action.
Chennai, India --
Against the backdrop of a growing water crisis in India, an ancient, subterranean, labyrinth-like structure is emerging as one solution to bolster its shrinking reserves: stepwells.
These intricate, terraced repositories were once the lifeblood of Indian communities -- developed centuries ago to store and access water for drinking, agriculture and industry, they also functioned as a local gathering spot.
Today, many of these architectural marvels have deteriorated -- victims of neglect, pollution and a rapidly urbanizing India, which is now the most populous nation in the world. But an Indian environmentalist has made it his new mission to tap into this technology of the past, to secure water for its future.
For the almost 20 years, Arun Krishnamurthy has worked to bring India's blighted bodies of water back to life through his organization Environmentalist Foundation of India (EFI). As part of the Rolex Perpetual Planet Initiative, EFI has restored 657 water bodies across 19 states -- from lakes to ponds, and most recently -- stepwells.
"Stepwell restoration is the next big implementation challenge that I would like to add to EFI's responsibilities because we have a greater responsibility now on protecting these historical assets, which are a testament to human intelligence," Krishnamurthy tells CNN during an interview in India.
EFI already draws on the stepwell ingenuity of its forebearers to guide its lake and pond restoration efforts, he adds.
"The engineering of it, land use, understanding the hydrological flow, the storage parameters: How was the embankment laid? Where was the palm tree planted? How was the canal cut?" Krishnamurthy says, "so taking lessons from the past, adapting it to the present-day challenges is what we are implementing."
Arun Krishnamurthy, founder of Environmentalist Foundation of India, has restored countless freshwater bodies.
Michelle Cohan / CNN
Despite his extensive experience rehabilitating freshwater bodies, Krishnamurthy says stepwells are uniquely demanding. Restoring these ancient structures calls for specialized traditional knowledge and craftsmanship -- and even after they are revived, vandalism makes their upkeep an ongoing struggle.
EFI hires local experts with generational knowledge relating to the specific wells they aim to revive.
It has just begun planning the renovation of a stepwell in Devanahalli, near Bangalore, that has gone completely dry. Although the stone infrastructure is mostly intact, Krishnamurthy says this stepwell will require some aesthetic improvements. It will also need community engagement and accountability to safeguard its future.
The storied history of stepwells
As one of the most advanced ancient civilizations in the world, India was known for its sophisticated urban planning -- from its grid-structured cities to its elaborate stepwells and temple tanks.
"Hundreds of years ago, there was no electricity, people were dependent on surface water bodies," Krishnamurthy says, "they needed deep down underground storage units slowly but steadily pumping water from (the) ground below to raise up -- so stepwells or temple tanks were created."
These ornately carved reservoirs capture and store rainwater, which slowly filters through layers of sand and porous stone, making it clean for drinking.
The addition of descending steps allowed people to access the water year-round, even as levels fluctuated.
Once vital during dry spells, these wells evolved into elaborate structures with pavilions and shrines.
David von Blohn/CNN
In India, water is considered sacred, so many wells were crafted as inverted temples, embellished with carvings and divine sculptures as an expression of reverence for the precious resource.
What began as primitive cavities dug into the ground, have transformed into architecturally significant, aesthetically appealing solutions to the water crisis, Krishnamurthy notes.
Restoring stepwells
EFI has restored two stepwells to date and has another six slated for 2026, according to Krishnamurthy. The Moosi Rani Sagar stepwell in Alwar, Rajasthan, was the first structure EFI restored in 2022, alongside Hinduja Foundation, the Prince Albert II de Monaco Foundation and Ashok Leyland.
Set at the foothills of the Aravalli -- the oldest mountain range in India -- the stepwell had long served as a vital water source for the city. But years of neglect left it in disrepair: solid waste accumulated, contaminating the water, and the once-robust stonework began to crumble. They repaired the infrastructure, removed waste, and improved water quality and quantity.
Environmentalist Foundation of India
Environmentalist Foundation of India
The restoration of the Moosi Rani Sagar stepwell in Rajasthan. Environmentalist Foundation of India
Krishnamurthy maintains that maximal conservation can be achieved with minimal intervention: these restorations do not depend on major modern technological enhancements. But they do demand a specialized workforce equipped with the generational knowledge to keep their architectural integrity intact.
"There's so much science behind it, the kind of material they use, the kind of artisan skill sets with which they developed and built them," Krishnamurthy says, "so learning all of it and working on stepwells has been quite a remarkable experience for me."
A country shaped by water
India's story has always been shaped by water. From the glaciers in the Himalayas to the wetlands of the south, the nation is home to a vast network of waterways. It is also home to one of the most populated river basins -- the Ganges -- which spans more than 2,510 kilometers (1,560 miles) and supports hundreds of millions of people.
The Ganges is continually classified as one of the most polluted rivers in the world -- chocked by untreated sewage, agricultural waste and industrial runoff.
This heavily contaminated river is considered extremely holy, believed by many Hindus to be the physical embodiment of the goddess Ganga. Water holds deep spiritual significance in India, where several religious traditions link elements of the natural world to divine beings or sacred energies.
Call to Earth: Reviving India's waters
24:03 * Source: CNN
Call to Earth: Reviving India's waters
24:03
"Water and nature worship has been an integral part of our cultural evolution," Krishnamurthy tells CNN.
"We understood that without water, there's no life," he adds, "for us, water is God, and water means energy, and thanking water is what most and all celebrations are about."
These celebrations, often involving offerings cast into the water -- from figurines to decorative plastic flowers -- take place daily, from the banks of the Yamuna River in Delhi to Chennai, on the Bay of Bengal. Unfortunately, Krishnamurthy notes, this practice contributes to pollution -- not just in natural waterways but also in stepwells.
"This irresponsible behavior towards nature, and cultural heritage structures, is the reason why we are in this mess," Krishnamurthy says.
It is very demotivating at times, Krishnamurthy confesses, but vows he won't give up.
To change the tide, EFI engages in public awareness campaigns, school programs and wall paintings to help build a sense of community ownership to ensure the long-term preservation of these important, life-sustaining structures.
"To even have the basic opportunity to work on some of these is, I think, a blessing," he adds, "and we are ready to give our fullest to it."