There was little fanfare when Rasbhari landed on Amazon Prime on 25 June. The Indian TV series, about a seductive teacher arriving in the small Uttar Pradesh city of Meerut, touched wryly on issues of teenage sexuality, sexual repression and the double standards for Indian men and women, but was absent of nudity or graphic scenes.

Only 24 hours later, a campaign of hate had built online. The show’s star Swara Bhasker, a Bollywood actor known for being outspoken against the Indian government, was inundated with thousands of tweets and threats, accusing the show of being obscene, of vulgarity, of being anti-Indian and anti-Hindu. Figures from the ruling Bharatiya Janata Party (BJP) were among those tweeting their disgust.

On IMDb, the website where authorised accounts can rate TV series and films, thousands of damning and, it seems, coordinated reviews poured in. The show currently ranks 2.1 out of 10, with 80% voting for the lowest possible score: one.

Over the past year in India, streaming services such as Netflix, Amazon and Hotstar – free from the regulation that controls Bollywood and traditional Indian television – have hosted a new, more progressive breed of TV show. Unshackled from censors, these shows have addressed sex, sexual violence, homophobia and caste inequalities, and critiqued the sinister side of rightwing Hindu nationalism and the persecution of Muslims.

The backlash has been fierce. As well as Rasbhari, shows such as Leila on Netflix, which opened with the lynching of a Muslim man, or Paatal Lok, which shows police brutality, rape and attacks on Muslims, have been the targets of vicious, relentless and far from spontaneous attacks.

Bhasker said she knew Rasbhari would court controversy, but was taken by surprise by volume of the hatred. She has repeatedly criticised the Indian prime minister, Narendra Modi, and the BJP government and their Hindu nationalist agenda, and believes her dissenting political views, more than the content of the show, have made her a target.

“They are attacking my real-life persona under the garb of a TV series that barely any of them have seen,” said Bhasker. “I expected some trolling and people being uncomfortable with some of the sexual elements, but I did not expect it to come under the kind of agenda-driven scrutiny it did. It’s like the fake ratings on IMDb are a mob punishing you for being a dissenting voice.”

Streaming services such as Netflix have exploded in popularity in India, particularly among the 50% of its 1.3 billion population who are under 25. Bhaskar said the BJP, and its militant umbrella organisation the RSS, which is dedicated to a Hindu nationalist cultural agenda that aims to block western influences on India, were evidently concerned at the reach of the platforms.

In June, the RSS called for strict laws against web series that “hurt the fabric of Indian society”. This week, Prasoon Joshi, chairman of the Central Board of Film Certification (CBFC), tweeted criticism of Rasbhari’s “irresponsible content” and said “creators and audiences need to seriously rethink freedom of expression”.

“They have suddenly found that the digital space, which has become so wildly accessible to so many Indians, especially young Indians, is perhaps unwittingly becoming a space for dissent and critique which is challenging the Hindutva [Hindu nationalist] agenda,” added Bhasker. “So now they are now calling for it to be censored.”

The Hindu nationalist agenda has been encroaching on India’s cultural space for several years. In 2018, when the US series Quantico aired an episode featuring Hindu terrorists, its Indian star, Priyanka Chopra, was subjected to vicious trolling and forced to issue an apology. Similarly when Sushant Singh, star of the beloved true crime show Savdhaan India, participated in anti-government protests last year, he was fired from the series.

Anubhav Sinha, a celebrated film-maker who has spoken out against the BJP government, witnessed the same phenomenon. In 2018, when he released his film Mulk to critical acclaim, it had a 9/10 rating on IMDb. “Then, overnight, some 5,000 accounts gave it a one-star review. I couldn’t fathom it, until I realised it was a smear campaign. It was so heartbreaking,” he said. “They will try to bring down the movies of people they see as ‘anti-national’.” Sinha complained to IMDb but says it did not address the issue. IMDb has not responded to a request from the Guardian for comment.

Shakuntala Banaji, a professor of media, culture and social change at the London School of Economics, said the trolling allowed for dissenting voices to be silenced without the government taking an active public role. “It’s intended to be viewed as a natural backlash – just civic Indians reclaiming their identity and what they believe in – when in fact it is the highly organised BJP IT cells,” she said.

She added: “The organised trolling against these shows is more about policing the public sphere than a genuine anxiety about Indian values. It is about saying, we have hegemony over absolutely everything.”