From the 6th to the 11th century, in the town of Aurangabad in northwestern Maharashtra, the Rashtrakuta dynasty and the Yadavs built a group of 34 caves. Each of these stone caves dedicated to three religions, Buddhism, Hinduism and Jainism. Over the years, Ellora regarded as a legacy that reflects Indian rock-cut architecture. However, recent studies by Indian archaeologists have revealed a particularly interesting tradition of Buddhist monks praying in these caves.
They used cannabis mixed with plaster covering the painted walls and ceilings of the shrines, as well as clay and lime, to preserve the structure to the best of their ability. And it turns out that the cannabis in the soil mixture seems to have played a key role in preventing the decay of the UNESCO World Heritage site over the 1500 years of its existence.
Both Rajdeo Singh, an archaeologist chemist with the academic staff of the Archaeological Survey of India, and Milind M. Sardesai, who teaches botany at Dr. Babasaheb Ambedkar Marathwada University, say the mixture has prevented the plaster from decaying for more than 1,500 years.
Caves are breathtaking examples of rock architecture that testify to the imagination and artistic talent of their creators. Wrote Singh and Sardesai in the journal Current Science.
For the study, they analyzed the clay plaster of Buddhist Cave 12 using techniques such as Fourier transform, infrared spectroscopy and stereo-microscopic studies.
They were able to isolate cannabis specimens from the clay plaster and were able to conclude that it was cannabis Sativa that had helped to prevent insects at Ellora.
Cannabis fiber appears to be of better quality and more durable than other fibers. In addition, the gum and sticky properties of cannabis may have helped clay and lime to form a firm binder. Said Mr. Sardesai.
According to the researchers, the concrete-like substance, called hemp, may have provided Buddhist monks with a healthy, comfortable and aesthetic living environment.
Because hemp plaster can store heat, is fire-resistant and absorbs about 90 % of airborne noise. A peaceful living environment for the monks created in the Ellora Caves, they added.
Several studies have estimated that hemp can last 600-800 years. Which explains why the lifespan of the caves has doubled despite damaging environmental factors such as increased humidity inside the caves during the rainy seasons. Ellora proved that only 10 % of the cannabis mixed with clay or lime in the plaster can last more than 1,500 years. Said Mr. Singh.
As Mr. Sardesai pointed out, “Cannabis has gained a bad reputation in India because of its narcotic properties”. However, artists of the sixth century were able to measure its properties.
They understood that it could regulate moisture and that it would play a key role in pest resistance. Fire resistance, non-toxicity, high water vapor permeability, and hygroscopic properties – qualities that kept Ellora undamaged throughout the years . In the nearby town of Ajanta, artists did not use hemp. Which explains why insect activity has damaged at least 25% of the paintings.
Considering that in India, the cultivation, transportation, possession, and use of marijuana are prohibited by Indian law . (Although things seem to be changing further north in Uttarakhand). Suffice it to say that in today’s India. It could be a long time before we decide to use cannabis for construction purposes.