PREMA beats out a lulling rhythm on her double-ended, mridangam drum. As she does so, sitting cross-legged on the floor of the small room that is her entire home – stove in the corner, bedroll to one side – she is demonstrating one way in which trans women have earned money for centuries here in India, where they are considered to have special powers. A 3,000-year-old South Asian tradition of a third gender, of eunuchs, means that while these trans women, frequently known as hijra, are often outcast and marginalised, they are also revered. Their music and dance is considered a blessing at weddings and the birth of boys. People give them money for their benedictions. Their touch on a baby's head can, it's believed, bring great things; a curse is considered even more powerful, and is feared.

But Prema, who lives in a small community of 25 transgender women in a busy market area of Delhi, no longer dances at weddings. Instead, she and the others in her small community, survive by begging in the local streets, or at the train station, trading blessings for money.

“I bless people,” says Prema, “saying, 'If you don’t have a boy may God then give you a boy.' Or, 'If you are barren then may God give you a child.' A lot of them out of love and respect give us clothes, money, supplies.” Recently, however, she notes, traffic police have started preventing them from begging. “And this is the only way I can get money,” worries Prema. “Originally I did sex work, but I’ve stopped.”

Few in this transgender community still do sex work. All but two have been diagnosed HIV positive. Like a large tight-knit family, they nurse each other through illness and provide mutual support through the difficult times. Occasionally one of them falls ill: with tuberculosis, herpes or some other condition. While the government provides their drugs, their chief external support comes from Shalom, a clinic and outreach project which is part-funded by EMMS International, the Edinburgh-based charity that has brought me here to Delhi.

Shalom provides a vital lifeline. Not long ago, Prema was so ill with tuberculosis that she was out of work for three years. During that time she grew weak and emaciated. She pulls out a small album of pictures of herself – drawn, skeletal, hollow-cheeked, a shadow of her vibrant, yet gentle, current self.

During that time it was her "sisters" in the community – along with Shalom support worker Malti Mehra, who accompanies us now – who kept her going. “I had become very thin,” she says, “I was admitted to the Shalom clinic two or three times and I was not very financially very equipped, but Shalom did not charge me. I think if I hadn’t been admitted to the Shalom hospital I would not have been able to live.” For Prema, Malti has been a key support over the years. “I share everything with her. She visits my home. I tell her everything.”

The two first met around 10 years ago when Prema was a volunteer on a project run by an NGO, Sahara, in this area which initially offered support to drug users and later focused on people with HIV. Prema recalls that it was Malti who first persuaded her to get the HIV test that led to her positive diagnosis. Malti also suggested she use a condom. “I didn’t even know what a condom was. I asked her, ‘How do you eat it?’”.

This small colony is a loose echo of what most people in India understand as the hijra community, tight-knit, almost matriarchal in its structure. Prema and her sisters, however, do not like the name hijra, a term they say is only really applied to them by people who “talk dirty in sexual terms”. Like the word chakka, which means “neither woman nor man”, it's often used as an insult. Prema prefers the word kinnar (which means transgender in Hindi) or the term "TG". “We feel bad when we are called hijra or chakka.”

Sitting on the floor in Prema’s room, the group demonstrate the clapping that distinguishes the hijra or kinnar, communicating mood and message. Their flat palms strike against each other, horizontally, fingers spread. The clapping, Prema explains, can mean different things. "For anger it’s a different tone. To display love it’s a different tone. To display happiness it’s a different tone.” Often they clap out their anger when people tease them or call them names.

Their presence, she notes, provokes both fear and respect. “In India, people believe that if we curse anyone it will be really bad, and if we bless anyone it’s going to be really good. So if we touch somebody on their head, especially children, they will be blessed. But if we curse them then that curse is going to ruin them for life. The respect comes from that.”

But they also feel discriminated against and mocked. “Some people tease us. Some of them even fight with us. It can be physical."

Despite their special position in Indian society, the transgender community is vulnerable. They are marginalised and frequently forced to live outside the Indian bedrock support system of family. Many are shunned by their families, stripped of the inheritance they would have received as male sons. Frequently they are not educated and find it hard to gain work.

Their communities are associated with high levels of substance abuse. Studies have found they also have a high HIV prevalence (8.8%). Meanwhile, myths and misconceptions hang around them. The belief in parts of Indian society that it is not possible to get HIV from sex with a trans woman, has exacerbated the HIV problem within the community. “After having two or three kids, men, often get bored with women," says one member of the group, "and then they come to the TG community. They prefer the TGs to women. They think you will get HIV if you have sex with a woman, but not with a TG.”

Stories of hijras kidnapping children and changing their sex are folk mythology in many parts of India. As high-profile transgender activist Laxmi Narayan Tripathi has pointed out: “Crimes by hijras are often exaggerated and the hijras are chastised. Disproportionate punishment is meted out to us by the police and the public.”

Trans women are also vulnerable to physical violence and rape – and in India no laws exist to protect male or transgender victims of sexual assault. Most members of this Mori Gate community have experienced extreme and shocking sexual violence, including forced anal sex and gang rape. One tells me she was “picked up by 35 guys”. Another says she was raped by eight to 10 men: “Some of them came on a bike and picked me up. They took me back to somewhere where there was this whole group. They robbed and raped me.”

“We all experienced it initially,” says Prema, “but now we know the tricks of the trade. We protect each other. You find a mentor, a mother, a guru, who tells you how to deal with things.”

Yet, India is arguably more accepting of trans people than most other countries. Perhaps because they have so long had a notion of a third gender (the Kama Sutra provided a description of sexual life of people with "third nature" or "tritiya prakriti"), Indians seem more at home with such ambiguity than we are in the West. Moreover, it was British colonisers who, on taking power in India, passed a law classing all eunuchs as criminals. Despite this, the hijra never disappeared. The last census in India counted the number “third-gender” individuals, and revealed a population of 490,000. Meanwhile, many high-profile transgender figures have emerged: last year, Madhu Kinnar was elected as India’s first openly transgender mayor; and in 2014, Padmini Prakash became the country's first transgender individual to anchor a daily television news show.

The rights situation is, however, complicated. On some levels the country seems highly progressive: in April 2014, the Indian Supreme Court recognised transgender people as a distinct gender and, last year a private members bill on transgender rights was passed. Yet it remains illegal for a man to have sex with another man (thanks to another colonial era law, article 377 of the Indian penal code). And last month, a private members bill to decriminalise gay sex was defeated.

PREMA'S days involve doing the the household chores, talking to the other kinner, washing clothes. Around 4pm she takes a walk, goes to the red light area and begs; by 6pm she is back. In her free time, she watches television on the small old screen that sits propped in the corner of her single-room home. Her friend Moolani follows a similar routine. Each day that she begs, she says she earns 200-300 rupees (£2-£3).

At 50 years old, Prema has lived here longer than any of the others. She is, for some of the trans women here, a guru and mentor. Bindia, who is wearing a peach-coloured sari, is introduced as Prema's "sister. Alita is described as her “daughter”, and Salma as her “disciple”. This community is Prema's family, a babble of teasing and laughter. According to Shalom support worker Malti Mehra: “They don’t feel like they need to visit their own families, because this itself is a family to them.”

There’s a loud shout of “Namaste”, as another sister, Moolani, enters the room amidst a wave of music from her phone, and flops on the floor. She is exhausted, having been up since 4am (after coming back from a party at 2am) in order to collect her HIV medicine. She had to stand in a long queue at the hospital, but as she points out: “It is important for me to get medicine. The doctors give you a particular date and if you don’t come on those days you don’t get the medicine.”

The group flirt with the one man in our company. Some have boyfriends, others husbands. Prema declares that she had a boyfriend, “but he just wanted me for money". When asked about her own romantic status, Moolani grins and declares: “I have a lot of boyfriends.” Bindia is teased about her husband. “She’s not exactly married," someone in the group explains, "but she has got a guy. She treats him like a husband but they can’t get married. They are in a relationship.”

In India, hijra are frequently classified under the title MSM, "men who have sex with men" – a wide category which includes a host of groups, from gay males to the effeminate men often classified as kothi. Everyone in this community of kinnar is, they tell me, trans and “castrated”, as they have to be in order to be accepted into the community. Many have taken hormones, many have silicone implants. They are all, also, sexually attracted to men. "We hit on men," says Prema. "We love them. If we see any good-looking guy we flirt with them.”

Prema did not realise she wanted to "be kinnar" till she was about 17. As a child, she was scared of the TG people she met. “Especially when they clapped. I used to think they were going to kidnap me and take me away. But I was very curious whenever they would come and dance.” At the age of eight, she ran away from home, fleeing, she says, a broken family. Following her mother's death, she'd become one of many siblings looked after by a stepmother. “During that time I was very troubled. Very confused.” Later, she got into sex work because, she says, her lack of an education meant there was no alternative. For a while, as a teenager, she lived with her uncle. “There was a guy there and I started to have feelings for him, and I was also doing a lot of household chores. I did all the women’s chores. I was inclined to the attitudes and behaviours of women.”

Now, she wants to be treated like a woman, “but nobody ever does that”. She recalls with pleasure, a moment from earlier today. “I went to the shop to get blankets, and the shopkeeper was talking to me and was asking. 'Where is your man?' I said, 'I am all alone and we don’t have very much.' And he said, 'Where is your husband?' Then I clapped and said, 'I am transgender.' He had not realised.’”

Despite the way girls are treated and devalued in many parts of India, the kinnar of Mori Gate want, above all, to be female. “It is not forced" says Moolani. "It is out of desire. We want to live life on our own terms. Our parents will not be happy, but this is for our happiness we do this. We do it for ourselves. It’s just our heart’s desire.” Of course the path to that heart's desire is not yet an easy one, even in a country like India, with its long history of embracing gender variety and ambiguity.

But they seem undaunted. When I ask Moolani if she feels discriminated against, she says: “ I don’t really care. I am just who I am.”

* As part of a critical and palliative care initiative, EMMS International funded Shalom's move to its current location in north Delhi, paying for the re-establishment in a new location of Shalom's 10-bed mixed ward, and the office from which its community workers do their outreach work. You can help support EMMS projects in India, where they are currently involved in gender-related and palliative care projects, either online at emms.org/sendalight or through donating £5 by texting GIRL to 70660