NEW DELHI, India — An hour before the Metallica concert in Bangalore last year, the event's organizers came to 26-year-old Chintan Chinnappa, a lawyer at Dua Associates, with some bad news. The program — running, naturally, on Indian Stretchable Time (IST) — was behind schedule. Chinnappa's all-Indian band, Inner Sanctum, would not be opening for his thrash metal heroes after all.

“That really killed us,” Chinnappa said. “You dream about this, and then your dreams are shattered.”

Then, a few minutes before Metallica was supposed to take the stage, Inner Sanctum was back on the program.

“I don't know how it happened exactly,” Chinnappa said. “The guy doing sound had heard us before, and he recommended us to the organizer. He said, 'Listen, they're a band that Bangalore loves, and you must get them on stage.'”

“After the event, the management of Metallica spoke to us, and they were so thankful, because otherwise the crowd was so frustrated, because there was rain and all of that and they were waiting for bands to perform. After we performed, the response was massive.”

Surprised? Don't be. It may be better known for saccharine Bollywood love songs and Hindu devotional tunes, but India has an enduring love for rock-metal acts that have fallen off the radar in the United States — if they're even still alive.

For college graduates from 22 to 45 years old, forgotten bands like Deep Purple, Dire Straits and, yes, Iron Maiden remain immortal — thanks largely to the country's legion of engineers.

More from GlobalPost: India's Other Bollywood

“Engineering college computer servers have been crucial to the propagation of heavy metal in India,” music critic and concert promoter Arjun Ravi wrote recently in India's Sunday Guardian.

As a result, metal heads here — weaned on math homework and raised with an eye to the software industry — can look radically different from the headbangers of the American heartland or the costumed nihilists of Swedish death metal.

Hard rock and heavy metal is associated (rightly or wrongly) with working class anger in the United States and Europe. But in India, love for thrash, doom, speed and death almost always requires a college degree.

Headbangers still live with their parents, who tolerate music they call “noise” as long as it doesn't interfere with their kids' jobs or marriage prospects. And many rockers like Chinnappa, a buttoned-down lawyer, look and dress accordingly.

“There are two types of fans,” said Vibhas Venkatram, the 24-year-old drummer for Eccentric Pendulum. “There are these guys who believe metal heads are supposed to be some [certain] way. Even if they're working in a software company or a bank they have long hair and they come on stage with that long hair and head bang.”

“But there are these other guys who are short-haired, with glasses, completely geeky looking yuppies, I guess you could call them,” added Venkatram, a graduate student with a modest ponytail and a goatee who until recently was working with the Indian Institute of Astrophysics.

“At the end of the day, we're all just metal heads.”

More from GlobalPost: India's new license to rock

At the same time, metal acts like Chinnappa's are pushing beyond classic thrash, even as Indian electronica thrives on the club scene. And while this year's concert program features geriatric rockers like Megadeth, Slayer, Guns-N-Roses and even Carlos Santana, there are signs of change on the horizon.

Earlier this year, contemporary metal headliner Korn played Bangalore and New Delhi. Along with the Slayer-Santana “Rock 'n India” concert in Bangalore later this month, the “Bacardi NH7 Weekender” will bring rock-metal fans together with fans of folk and fusion music, as well as dubstep, drum and bass and reggae in a massive, six-stage event that will hit Delhi, Bangalore and Pune, Maharashtra. And trance-haven Goa's 5-year-old Sunburn Festival will this year bring its signature mix of Indian and international electronica to Delhi and Mumbai.

“I used to call it 'Third World Rock,'” said Ravi, who also runs a music website called indiecision. “You had bands like Deep Purple, the Scorpions, Aerosmith, all these bands [that were well past their prime] coming to India. But now, over the last four or five years, there has been an influx of more contemporary popular acts.”

Along with Korn, contemporary metal acts like Australian rockers Karnivool, French death metal band Gojira and the Prodigy are now hitting Indian shores, Ravi said. And in the world of electronic music, India is already a regular feature on the concert circuit, with David Guetta, Afrojack, Armin van Buuren and Avicii performing over the past year or two.

“This year, for example, it's such a great year for metal, because so many more contemporary acts are coming to India,” Ravi said. “And it's all because of these kids. None of this stuff is available in stores.”

“You're not going to go to Planet M [Indian music store chain] and get a Gojira album or a Karnivool album,” he added. “[They're coming here] because these kids have discovered these bands over the internet. And they're obsessive about these micro-niches — doom metal, black metal, and all the other many forms of metal that exist now have audiences in India.”

Blame the nerds. Indian Institute of Technology (IIT) campus festivals from Mumbai to Madras were the first to feature international acts like Finland's Ensiferum, Sweden's Katatonia, Opeth and Hammerfall, according to Ravi. And the metal heads have never looked back.

Indian bands like Bangalore's Inner Sanctum, Kryptos, Eccentric Pendulum and Slain, or New Delhi's Undying Inc, Skyharbor and IAFWAY are starting to make a splash, too. After opening for Metallica, Inner Sanctum is dotting the i's on a deal to play a major European metal festival later this year. Skyharbor's Keshav Dhar has drawn praise from industry heavyweights like ex-Megadeth guitarist Marty Friedman by uploading his tracks to sites like Soundcloud, resulting in collaborations with Ex-Tesseract vocalist Daniel Tompkins and a contract with UK-based Basick Records, according to Ravi.

“Within the domestic metal scene the shape and sound of metal is changing,” said Ravi. It's not just that dated, budget version of Iron Maiden or budget version of Mettallica anymore.”