Varun Soni is an adjunct professor of religion and dean of religious life at the University of Southern California. He is the first Hindu to serve as the chief religious or spiritual leader of an American university. The views expressed are his own.

(CNN) When I graduated from college 20 years ago, I embarked upon a spiritual journey across India to learn more about my Hindu faith and Indian ancestry.

Having grown up Hindu in the United States, my understanding of Hinduism was largely informed by temple visits and cultural celebrations, so I knew very little about how Hinduism was lived and practiced on the ground in India.

For more than a year, I traversed the length of India as a Hindu pilgrim, and I was profoundly inspired and transformed by the wisdom, beauty, and light of Hinduism.

But I also witnessed firsthand the dark side of Hinduism and I remain haunted by it.

I will never forget the day I set off on a camel safari from Jaisalmer, an incomparably romantic citadel in the Thar Desert. What started off as an adventure to reach the nearby border of Pakistan soon ended at an isolated village of "untouchables," a community often referred to as Dalits.

As an Indian, I already knew that Dalits had long resided at the very bottom of the Indian social hierarchy and were continually subjected to discrimination and disenfranchisement.

But as an American, I was shocked by what I encountered in the village -- abject poverty, malnutrition, illiteracy, children in desperate need of medical care, no running water or electricity, and a dried up well in the midst of the unbearable desert heat.

These villagers faced many of the same challenges and difficulties that 150 million other Dalits face in India today. Many Indians view Dalits as "polluted" based on their familial lineages and occupations. They are effectively segregated from society.

Program note: Go inside a mysterious Hindu sect on the premiere episode of "Believer with Reza Aslan," Sunday, March 5, at 10p ET.

They are forced to live in separate villages and drink from separate wells. They are prohibited from marrying outside their communities and are precluded from working in many professions. They are more likely to be victims of violence and sexual assault.

And in a country that has more poor, illiterate, and hungry people than any other country in the world, they are disproportionately represented among the more than 250 million people who live below the poverty line.

In so many ways, the enduring existence of "untouchability" is India's greatest sin and Hinduism's greatest challenge.

But this wasn't always the case.

Birth and rebirth

Hinduism, the world's third largest religion, traces its roots back to the most ancient extant religious text in the world, the Rig Veda. This text contains within it a scriptural passage that outlines a theoretical division of labor for an ideal Indian society based on four social groups: (1) priests and teachers, (2) rulers and soldiers, (3) merchants and traders, and (4) laborers and artisans. According to the Rig Veda, this division of labor is not predicated on a social hierarchy or dictated by bloodline.

JUST WATCHED India's sex education manual breaks taboo Replay More Videos ... MUST WATCH India's sex education manual breaks taboo 00:59

But nevertheless, over the course of many centuries and due to a variety of factors, a rigid caste system of social stratification developed in India that was based on status and kinship, with the priests at the top of the social hierarchy and the laborers at the bottom.

Even below the lowest caste of laborers are the Dalits, so low on the social hierarchy that they are outside the formal structure of caste altogether.

From a theological perspective, most Hindus believe that every human being has a soul that is reincarnated over many lifetimes, and the goal of Hindu life is to achieve liberation from the cycle of rebirth. Most Hindus believe that in order to achieve liberation, one must perform one's duty and cultivate the right action, wisdom, and devotion so as to achieve a higher-caste rebirth.

So within the context of caste, social and spiritual mobility happen between lifetimes, and it could therefore take many lifetimes to escape lower-caste social status and achieve spiritual liberation.

Photos: From the Beatles to bungee jumping: Rishikesh offers much more than yoga Photos: From the Beatles to bungee jumping: Rishikesh offers much more than yoga Yoga capital of the world: International Yoga Day, which is being celebrated on June 21, was proposed by Indian Prime Minister Narendra Modi in 2014 to the UN General Assembly and adopted unanimously. There's no better place to celebrate than Rishikesh -- the "yoga capital of the world." But there's much more to do here. Hide Caption 1 of 15 Photos: From the Beatles to bungee jumping: Rishikesh offers much more than yoga Rishikesh: Although the Beatles put Rishikesh on the map in 1968 with their trip to the Maharishi's ashram, the holy town on the banks of the Ganges river has recently become a hub for outdoor activities. Hide Caption 2 of 15 Photos: From the Beatles to bungee jumping: Rishikesh offers much more than yoga Aarti: Celebratory Hindu aarti sessions are performed nightly in Rishikesh, with music played and fire lit as offerings to the Ganges River. Hide Caption 3 of 15 Photos: From the Beatles to bungee jumping: Rishikesh offers much more than yoga The Beatles: The meditation hall at the former ashram of the Maharishi Mahesh Yogi in Rishikesh is festooned with graffiti, much of it celebrating the Beatles' visit in 1968. Hide Caption 4 of 15 Photos: From the Beatles to bungee jumping: Rishikesh offers much more than yoga Dear Prudence: The Beatles Ashram has been open to the public since 2015. Although much of it has been let in ruins, meditation caves like these inspired the song "Dear Prudence." Hide Caption 5 of 15 Photos: From the Beatles to bungee jumping: Rishikesh offers much more than yoga Peanut brittle: A market vendor in Rishikesh Town sells fresh peanut brittle. India accounts for 16% of the world's peanut production, according to the Food and Agriculture Organization of the United Nations. Hide Caption 6 of 15 Photos: From the Beatles to bungee jumping: Rishikesh offers much more than yoga Bustling markets: Rishikesh Town offers a sight unseen by most tourists visiting the holy city. It's akin to the more manic side of India, with busy street markets and bustling traffic. Hide Caption 7 of 15 Photos: From the Beatles to bungee jumping: Rishikesh offers much more than yoga Kirtan: Kirtan players in Rishikesh chant mantras to the gods that last for hours, often playing to no audiences. It is worthwhile sitting in on a session, and participation is usually welcomed. Hide Caption 8 of 15 Photos: From the Beatles to bungee jumping: Rishikesh offers much more than yoga Kailashananda: A view of the enormous Kailashananda ashram from the other side of the Ganges, with the busy Lakshman Jhula foot bridge connecting the two sides of town. Hide Caption 9 of 15 Photos: From the Beatles to bungee jumping: Rishikesh offers much more than yoga Yoga: Rishikesh boasts one of the largest clusters of yoga centers in the world. This yoga school features a giant tree wrapped in red rope to signify its holy status. Hide Caption 10 of 15 Photos: From the Beatles to bungee jumping: Rishikesh offers much more than yoga Cafes: Enjoying a coffee or tea at one of Rishikesh's many cafes is a good way to meet fellow travelers. These two Italian friends met in London and are spending a few months in the country. Hide Caption 11 of 15 Photos: From the Beatles to bungee jumping: Rishikesh offers much more than yoga Local fauna: Animals coexist with humans peacefully in Rishikesh, although monkeys can be aggressive with humans if they spot food. Hide Caption 12 of 15 Photos: From the Beatles to bungee jumping: Rishikesh offers much more than yoga Haridwar: A tree is converted into a red temple on the Ganges in the holy city of Haridwar, a one-hour drive from Rishikesh. Hide Caption 13 of 15 Photos: From the Beatles to bungee jumping: Rishikesh offers much more than yoga Nightly ritual: Haridwar has its own nightly aarti sessions, which are less catered to tourists. Be wary of false holy men looking to fleece you for a "donation," however. Hide Caption 14 of 15 Photos: From the Beatles to bungee jumping: Rishikesh offers much more than yoga Feet-dipping: Dipping your feet in the Ganges is tradition -- as displayed by this group in Haridwar. But the river runs rapidly and the banks can be slippery with moss, so do exercise caution. Hide Caption 15 of 15

As a social structure, the Indian caste system is unique in the world as it is based on birth and rebirth. But the philosophies, practices, and prejudices animating and informing the caste system can be seen throughout history in different cultural contexts.

For example, in his seminal work "The Republic," Plato articulated a theoretical division of labor based on different social groups much like the one found in the Rig Veda. Medieval European feudalism instituted a social hierarchy and division of labor based on kinship, similar to the caste system.

And the "one-drop rule" in the United States provided American courts with a legal doctrine to enforce segregation and support a racial hierarchy based on similar notions of purity and pollution as found in the caste system.

An outlawed caste system

Today the caste system in India is a complex and contentious web of social, political, commercial, and interpersonal relationships intertwined with hereditary groups, tribal and regional identities, and cultural practices.

Indeed, caste consciousness permeates the Indian cultural landscape and often transcends traditional religious boundaries, adversely impacting both Hindus and non-Hindus alike.

But fortunately, the future of the caste system in India looks a whole lot different than the past.

Since India's independence in 1947, there have been comprehensive efforts to address the dehumanizing impact of the caste system on lower-caste communities. For example, India's constitution legally abolishes "untouchability" and prohibits discrimination on the basis of caste.

Over the past two decades, the government of India initiated a number of ambitious affirmative action programs to ensure lower-caste participation and representation in higher education and government.

Photos: Ganesh Chaturthi festival 2016 Photos: Ganesh Chaturthi festival 2016 An Indian artist provides final touches to an idol of the elephant-headed Hindu god Ganesha before it is carried off for worship during Ganesh Chaturthi festival, in Hyderabad, India, on Monday, September 5. The Ganesh Chaturthi festival, a popular 10-day religious festival celebrated across India, runs this year from September 5-15 and culminates with the immersion of idols of Ganesh in the Arabian Sea and other local water bodies. Hide Caption 1 of 8 Photos: Ganesh Chaturthi festival 2016 Men carry an elephant-headed idol to worship during the Ganesh Chaturthi festival, in Hyderabad, India on September 5. Hide Caption 2 of 8 Photos: Ganesh Chaturthi festival 2016 A devotee holds his infant son before a statue of the Hindu god Ganesha during the Ganesh Chaturthi festival in Amritsar, India, on September 5. Hide Caption 3 of 8 Photos: Ganesh Chaturthi festival 2016 A Hindu devotee transports an elephant idol through the streets of Mumbai, India, on the first day of the festival, September 5. Hindu devotees bring home idols of Lord Ganesh in order to invoke his blessings for wisdom and prosperity. Hide Caption 4 of 8 Photos: Ganesh Chaturthi festival 2016 Devotees perform rituals in front of an idol of Lord Ganesh at a temple in Agartala, India, on September 5. Hide Caption 5 of 8 Photos: Ganesh Chaturthi festival 2016 An Indian priest offer prayers at the foot of a 58-foot-tall idol of Lord Ganesh, popularly known as "Khairatabad Ganesh," during the Ganesh Chaturthi festival in Hyderabad, India, on September 5. Hide Caption 6 of 8 Photos: Ganesh Chaturthi festival 2016 A devotee takes photos of an idol of elephant-headed Hindu God Ganesha with a likeness of a gorilla during celebrations in Mumbai, India, on September 5. Hide Caption 7 of 8 Photos: Ganesh Chaturthi festival 2016 A merchant naps while he waits for customers to buy his idol in Ahmadabad, India, on September 5. Hide Caption 8 of 8

Over the same period of time, nearly 200 million people in India were lifted out of poverty and are now part of a vibrant middle class that is less entrenched in caste identity. As India continues to urbanize, the caste system remains more of an issue in rural and agrarian communities than in the urban centers.

Ultimately, it will be up to young Indians to determine the future of the caste system. India has more young people than any country in the world, with more than 600 million people under the age of 25, and these extraordinary young Indians are poised to tell new stories about themselves and their country, new stories about reconciliation and redemption.

And by doing so, they will serve as a signpost to a new national consciousness, one that affirms and embraces the inherent dignity, self-worth, significance, and potential of each and every Indian.