Prominent Indian scholar and human rights defender Anand Teltumbde has turned 70 in a Mumbai prison amid growing calls for his release, writes the BBC’s Geeta Pandey in Delhi.

“Then they came for me, and there was no one left to speak for me.”

Professor Teltumbde often quoted these iconic words from German Lutheran Pastor Martin Niemoller, criticising silence when faced with evil, in his books and speeches.

On Wednesday, when he turns 70 in a Mumbai jail where he’s been imprisoned for 90 days, his family and friends are trying to ensure that he’s not greeted with silence.

Scores of letters and cards wishing him well on his birthday are expected to be delivered at Taloja jail where he’s being held.

“Anand is a respected academic who’s been shut away for completely dubious reasons,” Balmurli Natrajan, professor of anthropology at William Paterson University in New Jersey, who is among the people writing a letter to Prof Teltumbde, told the BBC.

“We want him to know that we are constantly thinking of him, reading his books.”

Counted among India’s best-known public intellectuals, Prof Teltumbde has authored 30 books and is known for his incisive writing on India’s harsh caste system.

Born to a Dalit (formerly untouchables in India’s rigid caste system) family, he worked in top positions in some of India’s biggest oil companies before moving to academia. At present, he’s head of the Big Data programme at the prestigious Goa Institute of Management.

A trenchant critic of the government, he’s described Prime Minister Narendra Modi as “more dangerous than Hitler and Mussolini” and a “narcissist par excellence”.

On 14 April, when Prof Teltumbde turned himself in to federal investigators on court orders, he joined 10 other activists, poets and lawyers who have been arrested in connection with what is known as the Bhima Koregaon case.

They are being held under the UAPA (Unlawful Activities Prevention Act) – an anti-terrorism law that makes it almost impossible to get bail.

Police accuse them of instigating caste violence at a Dalit rally in Bhima Koregaon village in the western state of Maharashtra on 1 January 2018.

Although those detained weren’t present in the village at the time, police blamed the violence on their speeches at a meeting the night before.

They are also accused of working in tandem with the Naxalites – banned ultra-left Maoist rebels – to “overthrow the government and cause chaos in India”.

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But Indian and international campaigners and rights organisations working for their release say they’ve been jailed for criticising the state.

“All the 11 activists have worked relentlessly to protect the rights of some of India’s most marginalised people, including Dalits and tribals,” Amnesty International said in one of the several statements it has put out in the past few months calling for their release.

Human Rights Watch has called the detentions “wrongful” and “politically motivated” and questioned why the government did not investigate the allegations that Hindu nationalist leaders may have had a role in the Bhima Koregaon violence?

In May, the European Parliament Subcommittee on Human Rights wrote to Home Minister Amit Shah saying it was alarmed by the “intimidation and harassment of human rights defenders” by the authorities.

The letter also urged India to immediately release all prisoners in view of the coronavirus pandemic – most of the detainees are elderly with underlying health conditions and thus at serious risk of catching the infection in overcrowded jails.

Prof Natrajan says India has always been “a marketplace of ideas”, pointing out that Nobel laureate Amartya Sen once called Indians “argumentative”. But in the past eight years, the space for argument and debate has been shrinking.

Prof Teltumbde, he says, has been setting the contours of key debates on globalisation and politics of caste and religion for the past 30 years.

“He’s been calling out caste deniers and Hindu triumphalism. He’s dared to point fingers at the powerful classes – he’s telling them, ‘here’s what you’re doing and how it’s put a majority of Indian people in misery’. And that makes him a dangerous man.”

Prof Teltumbde, says his wife Rama, was shocked when his name first came up two years back in the list of accused in the Bhima Koregaon case.

“We hadn’t even imagined it in our worst dreams that something like this could ever happen to us,” she told me on the phone from Mumbai.

“My husband is not a criminal,” she says, her voice breaking with emotion. “He’s an academic, a workaholic who spent 14-15 hours daily reading, writing and teaching.”

In his free time, she says, he would try to help the poor and the marginalised because he wanted to see an India that’s better, more just.

“To be thrown into jail for that is a very high price to pay.”

Since her husband has been jailed, Mrs Teltumbde has been allowed a weekly two-minute phone call with him.

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“I always ask him how’s his health? And how’s the prison food because I know the food there is very bad. He doesn’t want to worry us, so he always says he’s fine. And then he asks about his mother and our daughters.”

Mrs Teltumbde is the granddaughter of Bhimrao Ambedkar – the author of India’s constitution and an icon to millions of Dalits – and says she believes that her grandfather wouldn’t recognise today’s India.

“I don’t think he envisaged this kind of India where people are arrested for speaking their mind. We live in a democracy and freedom of speech is a right guaranteed under the constitution.”

But critics say it’s a right that is under grave threat in today’s India.

Those criticising PM Modi are attacked on social media by nationalist trolls, and activists and students opposing the government are being jailed. Most of the dissenters are charged under UAPA and being held in prison without bail.

Earlier this year, police in Delhi arrested several students who had protested against a controversial new citizenship law that critics say discriminates against Muslims. They were labelled as “anti-nationals working to break up India” by news channels friendly to the government. Female activists were slut-shamed on social media.

While most continue to languish in overcrowded prisons, Safoora Zargar, a pregnant female student, was freed after three months in jail following global condemnation.

“The government is playing with the liberties of people by arresting them under flimsy charges,” says Mihir Desai, Prof Teltumbde’s lawyer.

“The central charge against Prof Teltumbde,” he says, “is that he was helping the Naxalites by getting them recruits and spreading their ideology and that he was taking money from them.”

But when they raided his house, he says, they did not find any arms or cash.

The only evidence the police have put forth so far are four “letters” that they waved at a press conference.

Mr Desai says they are typed and unsigned and there are no addresses or email addresses on them.

He says they are not written by Prof Teltumbde or addressed to him – the one thing they all have in common is the mention of an “Anand” which is a common Indian name.

“These letters appear to be manufactured,” he says adding that “even if they are real, how do they prove that this Anand is Prof Teltumbde? Also, anyone can write anything to anyone, but is that proof? These can’t exist as evidence.”

The evidence is unlikely to stand scrutiny in court, Mr Desai says, but it’s the process that’s the punishment.

“If a person is jailed for 10 years while the case goes on, their life is ruined.”

As Prof Teltumbde completes three months in prison, his wife Rama says their only demand is for him to be freed on bail and the government to start the trial soon so that “his name can be cleared”.

A day before he was taken into custody, Prof Teltumbde wrote an open letter where he detailed the harassment he says he’s faced in the past two years – he wrote about how his home was raided, his Wikipedia page was vandalised, and how the government inserted Israeli spyware on his phone.

“As I see my India being ruined, it is with a feeble hope that I write to you at such a grim moment… I do not know when I shall be able to talk to you again.

“However, I earnestly hope that you will speak out before your turn comes,” he wrote.

By jailing him, Prof Natrajan says, the government is trying to crush the very people who are trying to reason and debate.

“But mark my words, Anand will not be crushed. You can jail people, torture them, kill them, but you cannot beat ideas.”