Mr Rajabian creates classical compositions using local Iranian instruments, but his latest project contains something largely forbidden in Iran: the graceful movements of a female classical dancer.

"The judge told me I was charged with publishing a woman singing and a woman dancing in my latest project, which 'causes society to go into prostitution'," Mr Rajabian said.

Mr Rejabian told the ABC he was arrested after Sony Music released his latest album online, along with a video featuring renowned Persian classical dancer Helia Bandeh.

He said he was interrogated and detained for several hours before his family paid for him to be released on bail ahead of his trial.

According to Iran's Islamic penal code, singing and dancing are not illegal but a person can be prosecuted if authorities deem their acts "indecent" or "immoral".

Authorities in the nation have long censored art, music and other forms of cultural expression, but Iranian law only vaguely defines what constitutes acts against morality.

Every event requires a permit from the Culture and Islamic Guidance Ministry, which also has the authority to intervene and cancel anything deemed immoral, according to the Centre for Human Rights in Iran (CHRI).

"The repression of Iranian women singers and musicians is not only part of the broad denial of freedom of expression in Iran, where any political or artistic expression disapproved of by the authorities is forbidden and criminalised, it also reflects the intense cultural repression Iranian women face in all walks of life," CHRI executive director Hadi Ghaemi said.

'They took my identity'

There have been restrictions on women performing publicly in front of men who are not their immediate relatives since the Islamic revolution of 1979.

Ms Bandeh, who performed to Mr Rajabian's music in the video that led to his arrest, said Iran's "complicated" rules regarding entertainment were a "grey zone".

"In the end, it all really depends on the individual and the connections you have that decide what you can and cannot do," she said.

"One artist can create a video clip with a dancer, another is arrested for it.

"If you choose to be an independent artist and you value to be able to express yourself freely, you are on the wrong side of the fence. You will get into trouble quickly."

Ms Bandeh spent six years teaching Persian classical dance both in Iran and abroad until, despite holding a permit, she was arrested last year.

Her workshop and home were raided, her belongings were confiscated and she was detained for one year.

"Persian dance runs through my veins and without it I might just as well not be there at all," she said.

"I felt they took my identity and there was nothing left inside of me."

Ms Bandeh now lives with her husband and children outside of Iran, where she continues to perform and teach.

She was saddened to receive the news of Mr Rajabian's arrest in connection to her dance.

"I could not believe that something so beautiful could be treated so unjustly … It is hard to express the depth of the sadness that lives inside of me for it," she said.

Mr Rajabian said he would continue defying Iranian laws that banned free artistic expression.

He said he spent three months of 2013 in solitary confinement in Tehran's notorious Evin prison, accused of insulting the values of Islam and spreading propaganda against the regime for an album he described on Facebook as being about the "absurdity" of the Iran-Iraq war.

His music label, Barg Music, which he said "supported banned artists, including many women", was shut down and his instruments and other equipment were confiscated.

In 2015, Mr Rajabian said he was again imprisoned, this time for two years during which he went on a hunger strike for 40 days.

"Even if I go to prison hundreds of times, I need female singing in my project, I need female dance along with philosophy and thinking," he said.

"Music is our only weapon. Philosophy in music are bullets for our struggle. Ultimately the goal is important."

A cultural paradox

Ms Bandeh said the criminalisation of such a "beautiful, soft and elegant form of art" was both "absurd and unjust".

"Instead, the country should show pride and support. I have spent my life presenting the beautiful side of Iran and our culture to people all over the world," she said.

"I have never expressed negative sentiments about our country anywhere. Still, here I am; a dancer, a criminal."

Ms Bandeh said many of her students also faced opposition at home, with some even beaten by family members for attending her classes.

Yet many Iranians felt dance was a part of their culture, she said, including dancing at weddings and private parties.

"But as soon as the dance is presented as an individual form of expression, an art, the perception is often completely different," she said.

"A strong women that dares to express herself individually suddenly becomes threatening. Instead of respect, it creates fear."

But for Ms Bandeh, dancing has been her lifelong passion and she has no intention of stopping.

"Persian dance connects me to the core of my soul, my culture and my people," she said.

"I feel it is my goal in life to express our history, our culture, our joys and our struggles through this beautiful art form."

'Denial of freedom of expression'

Kaveh Taheri, a Turkey-based Iranian researcher, investigative journalist and founder of political studies institute ICBPS, said Iranian authorities have banned 52 women musicians from performing since early 2019.

"Iranian women — as half of the nation's population — have no right to sing publicly or dance, even by stealth if the authorities find out," he said.

Forbidden to perform in public, many female dancers in Iran use their social media accounts as a type of virtual stage.

Last year, a popular social media movement called #dancingisnotacrime went viral, in protest of government censorship.

The movement was sparked after 17-year-old Maedeh Hojabri confessed to crimes on Iranian state TV when authorities clamped down on her Instagram account, where she had posted videos of herself dancing without a head covering.

Her story inspired the viral protest of thousands of Iranian women around the world filming themselves dancing in protest.

Mr Taheri cited numerous cases of performers sentenced to prison terms and/or lashes, including 15 women and men in 2018 imprisoned for alleged "participation in the production of 'vulgar' music and images and its dissemination through anti-regime satellite networks".

Female singer Negar Moazzam also received a prison sentence for performing solo in 2018, Mr Taheri told the ABC.

That same year, Iranian state TV broadcast apologies — which appeared to be filmed in prison — of several women, who were briefly detained for posting videos of themselves dancing on Instagram, according to a report by Human Rights Watch.

Sarah Leah Whiston, Middle East director at Human Rights Watch, said at the time that the incident was "equal parts abusive and embarrassing" and "a new low for the Iranian authorities".

Another incident in 2014 made headlines across the world when six Iranians were arrested for appearing in an "obscene" video dancing to Pharrell Williams' song Happy.

They were sentenced to up to one year in prison and 91 lashes, their lawyer said, but AP later reported that their prison sentence would be suspended as long as they did not commit any more crimes.

The Iranian embassy in Canberra, the Parliament of Iran and the Ministry of Justice did not respond to requests for comment.

Tehran's thriving underground music scene

Such restrictions have pushed Iran's music and dance scenes underground.

While Western pop music has largely been banned, a wave of locally produced hip-hop, rock and techno have found their audiences online.

Mina Kafashan is one part of Iranian techno duo Grey Wolves Noise.

She and partner Mehdi Darzi have been creating music in Tehran's underground techno scene for the past two years.

They have faced restrictions from authorities' countless times and cannot play their electronic music at any mix-gender festivals, as Ms Kafashan would face too much scrutiny as a female musician.

"We can't even dance while we're performing. It's funny, but a big pain for us," Ms Kafasha told the ABC.

The couple, who are both sound engineers, create their music from scratch using synthesisers and electronic beats.

But despite their hard work, they said they cannot break out into the larger electronic music scene because of restrictions. They instead launch their music on social media.

Because of government restrictions and political issues, Ms Kafasha said there is no way to "show our art or make people familiar with what we do".

"We might have some performances in some small places with few audiences, but they are all without [Government] authorisation," she said.

Despite working "really hard", she said their music still has no platform inside Iran.

"We're somehow anonymous in our country," she said.

"We're not free to do what we want, and we always have to present ourselves in a really restricted frame."