Dalits are at the bottom of the Hindu caste system and despite laws to protect them, they still face widespread discrimination in India, writes Natalia Antelava.
As the glass flew across the room and straight into the wall, a dozen or so men stopped drinking their tea.
Dr Vinod Sonkar threw money on the counter - enough for the tea he drank and the glass he had smashed - and walked out.
Dr Sonkar's soft voice turns angry as he describes the scene.
For years, he says, he worked hard to leave behind his childhood of poverty, abuse at school and teasing at university.
By the time he had walked into the Rajasthan teashop, he had turned his life into a success story.
He had a PhD in law and a teaching position at a Delhi university.
Yet, as the shop owner handed him his tea, he asked him what caste he belonged to.
"I am a Dalit," Dr Sonkar said.
"In that case, wash your glass when you are done," the shop owner said.
"He didn't want to touch whatever I had touched. I made it impure. I am an untouchable," says Dr Sonkar.
Margins of society
India is well known for its caste system, but not many associate the world's biggest democracy with what Dr Sonkar, and many other Dalits, call an apartheid-style state.
"Unfortunately the Indian government, made up of the upper castes, has successfully convinced the international community that caste discrimination is an internal, cultural issue. But the truth is, it affects the very way this country is run," Dr Sonkar says.
Dr Sonkar, who in his thesis compared affirmative actions in India with those of post-apartheid South Africa and the United States, argues that in India despite all legal provisions, 15% of the population is still kept on the very margins of society because of untouchability.
India's constitution banned the practice of untouchability - in which members of India's higher castes will not touch anything that has come in physical contact with the Dalits, the lowest caste.
Recently, an organisation called Video Volunteers, which runs a network of community correspondents throughout India, launched a campaign called Article 17, named after the constitutional provision that banned untouchability.
They are now preparing to file a lawsuit in the Supreme Court and ask the government to take steps to stop untouchability practices.
The campaign and the lawsuit are based on video evidence gathered by Dalits themselves.
The short clips that come from all over India include a man who complains that a local barber refuses to cut his hair, a group of children who are forced to eat lunch separately from their classmates and women who walk for hours to fetch water because they are not allowed to use the public tap in their village.
None of the footage on its own is particularly dramatic, but the persistent, systematic discrimination that it documents is deeply disturbing.
"It's like you are born with a stamp on your forehead and you can never get rid of it," says Amit, one of the community correspondents.
Amit's village in the northern state of Haryana is just a three-hour bumpy drive away from the capital, and yet Dalits here are not allowed to enter temples or visit houses of the upper castes.
"Today, here in Haryana, we the Dalits are still being tied to trees and beaten by upper caste people. Police do nothing because none of the policemen are Dalit," Amit says.
Amit and his neighbours admit that things are slowly changing.
There are now laws protecting Dalits and affirmative action programmes. And Dalits have worked hard to increase their political power - several states have even elected Dalit chief ministers.
But, only a very few manage to break out of the cycle of poverty and caste that they are born into.
Untouchability helps to lock Dalits, who traditionally do the dirtiest manual jobs, in their occupations.
Even if a Dalit scavenger can afford to buy a cow and sell milk or open a shop, for example, upper caste customers are unlikely to buy any of the produce.
In Amit's village Ladwa, like in most of India, no Dalits own land although his friend Vimal has moved into a house he bought from the upper caste members.
It's a spacious, solid building but the neighbourhood has changed.
"As Dalits moved in, all upper caste neighbours moved out, so the prices have really come down," Vimal says.
But, he admits that discrimination is not limited to the upper caste, within the Dalit community there are many sub-castes and hierarchies.
"We also need to stop discriminating against each other and to be more united as we fight for our rights," adds Vimal.
For many Dalits education is the only way out of poverty, but that isn't easy.
Dr Vinod Sonkar completed one of his degrees via a correspondence course because he found teasing in the classroom unbearable.
Today, Dr Sonkar is the only Dalit professor in his university.
I ask him to name an influential Dalit academic. He can't. A big name journalist? There isn't one, he says. A Supreme Court judge? Two out of hundreds appointed in the last 65 years.
In Sanskrit, the word Dalit means suppressed, smashed, broken to pieces.
Sixty-five years after Indian independence, Vinod Sonkar tells me: "We are still Dalit, still broken, still suppressed."