Inside the flooded cavern ‘Angelita’ in the Mayan city of Tulum, Mexico, wispy fingers extend out of a swirling layer of hydrogen sulphide, curling towards a group of divers, one of whom was a 4 foot 11 inch tall woman from Chennai. Cutting through the toxic — and stinky — layer of gas to head to the bottom of the cavern, the divers reach the edge of light. From here on, it is pitch dark. Fifty metres underwater, only rotting dead trees lie there, like extras in a Tim Burton movie.

Suddenly, the grim reaper on the warning sign board outside the cave makes a lot of sense. But 24-year-old Neela Bhaskar doesn’t stop: this is her first step towards becoming India’s only female certified full cave diver.

Scuba diving is still nascent in India, and cave diving is virtually unheard of. The country has few flooded caves, which is why, in 2016, Neela travelled to Mexico to get her certificate in cave diving.

“Cave diving is a step beyond scuba diving, a lot more difficult. There is a literal ceiling over your head, so you can’t go up anytime you want,” says Neela on a phone call from Hamburg, Germany, where she is currently pursuing her Masters in Classical Indology. She is also a trained classical singer and Bharatanatyam dancer.

Neela calls cave diving — all technical diving — as a way to cheat Nature: “In recreational diving, we start coming up as soon as we cross the recommended time, after that you are at risk for decompression sickness,” she says, explaining how rapid change in pressure causes nitrogen bubbles in the body. Called bends, they can result in cramps, numbness, nausea, and paralysis. But technical divers exceed the underwater time using a special mixture of gases to breathe and more efficient diving skills.

During her training in Mexico, Neela explored over 30 caves. “If you are in the South of Mexico, there is a high chance that you are standing on top of an extensive underground cave system,” says Neela. The lush jungles of southern Mexico are home to multiple cenotes: deep sinkholes flooded with freshwater, due to collapse of underground caverns.

Often, the caves they explore are pitch dark, illuminated only by cannister battery lights divers carry. “Imagine getting lost in a cave when you have no idea what is up or down, forget where the entry or exit points are,” she says. Which is why, divers focus on the exit, more than the entry point.

However, her main challenge was not nerves or strength or lung power — she can comfortably carry four cylinders, weighing 75 kilograms, almost double her 45-kilogram body weight. It was focussing.

“These are realms of the world that have been kept hidden from us until we developed the technique of cave diving. There is so much we don’t know that initially, it was hard to not stray away and explore the caves,” she says. She has seen skulls of turtles, centuries-old stalagmites and stalactites perched precariously on the cave walls. One wrong hold could bring years of history crumbling to dust. “These caves weren’t meant for humans to live in. You need to be respectful of that.”

Moreover, underwater, you have limited time, and can’t talk to your fellow divers. Straying away from the plan you mutually agreed upon is not an option.

Born to dive

“I have always felt at home inside water,” says Neela. Until she was 13, she grew up in Thiruvanmiyur. “I lived next to the sea for a long time, so some of my earliest childhood memories have been in water. I would wonder what is out there in the ocean.”

After she turned 18, she went to Puducherry to learn scuba diving. She soon became a recreational scuba diving instructor, in association with PADI (Professional Association of Diving Instructors). She then took up technical diving classes with the help of her friend, Julien Fortin. She later went to Planet Scuba Mexico to train as a full cave diver.

Before cave diving, Neela used to be a wreck diving instructor . “We tie a thread to a post outside the ship, and then take the spool with us inside, so we know our way out,” she says, “It’s funny seeing commonplace things like the toilets in such a surreal surrounding, with a host of wildlife growing on them. You can hear the water gushing in and out of the wreck. Sometimes, the force of it can throw you to the walls!”

Still, for Neela, diving goes beyond the thrill it provides — it is an education into the harm humans are causing to the ecosystem. “It is hard to care about the ocean when all you can see in front of you are bluish-green stinking waters. But when you see firsthand the variety of life forms that exist, and the number of them caught in floating plastic, it is impossible not to care,” she says. Which is why her plan for the future is to take more people on research and exploration trips around the Indian coast, diving headfirst into new challenges.