As the sun in all its tropical fury drifts west over the Arabian Sea, rush hour sets in on the coastal megacity of Mumbai. India’s largest metropolitan area, the city and sprawling suburbs are home to an estimated 20 million people. As the clock nears 5, Mumbai’s streets grow congested with buses, taxis, cars, rickshaws and bicycles. Professionals and laborers alike elbow past one another on the crowded sidewalks, hurrying home after a long day’s work. As with most weekday evenings, traffic is stop and go.

Dharavi — a shantytown on the city’s north–central outskirts that has gained worldwide fame as the real–life setting for the Oscar–winning film “Slumdog Millionaire”— experiences rush hour no less frenetically. Taxis, trucks, rickshaws, even the occasional cow push through throngs of pedestrians, all sharing the same narrow, unpaved streets.

Roughly a million people live in this impoverished, underserved and cramped area, no larger than a single square mile. Poverty–related illnesses, such as scabies, tuberculosis, dysentery and fungal and upper respiratory infections, are commonplace. According to a 2006 United Nations Development Program report, Dharavi has one toilet for every 1,440 residents.

Most Dharavi residents work low–paying, unskilled jobs in nearby factories and sweatshops. Many are children who do not attend school. In Dharavi alone, there are an estimated 15,000 single–room sweatshops.

A few residents make ends meet by hocking any variety of knickknacks, household wares and food items from small carts that line Dharavi’s winding streets. Evening rush hour for these street vendors, such as 69–year–old Mary John, is a peak time for sales.

The widow of 16 years focuses her attention on the passers–by, determined to lure a potential customer to pause a moment at her booth, which specializes in teas, cakes and candies. Though she earns a pittance from sales — far from enough to cover basic living costs — she smiles easily and hustles her goods with the charm and energy of a much younger woman.

But as dusk slips away and foot traffic thins out to a trickle, Mrs. John’s mood suddenly darkens. She shutters her cart for the night and begins to explain candidly and without self–pity that she and her family are struggling to survive.

Mrs. John’s husband had neither savings nor life insurance. When he died, she found herself broke and alone responsible for the care of her children. Ever since, she has awoken every morning at dawn, opened her stand and sold teas and snacks until nightfall.

After her son’s sudden death several months ago, however, she found herself struggling to deal not only with grief, but also with how to make ends meet. The loss of her son’s income has left her and her family in dire straits.

“Rent is 1,500 rupees [$30] a month, not to mention the cost of electricity, water, gas, meals on the table, health care and education for my two grandchildren,” laments Mrs. John. “My daughter–in–law works as a cook from 6 a.m. to 11 p.m. I work all day. But still, survival is the hardest thing.”

After locking up the stand, Mrs. John hastens home to prepare dinner for her 12–year–old granddaughter Jini. The agile 69–year–old leapfrogs a foul gutter, darts to the right and disappears down a dark alley. Dharavi’s concrete one– and two–story houses huddle tightly together; almost no space separates them and narrow alleys serve as footpaths. A few moments and sharp turns later, she arrives at the front door of her one–room, ten–square–foot house.

She enters and discovers her granddaughter is not alone but chatting with Sister Leema Rose, one of the four Nirmala Dasi Sisters living in the neighborhood. Though Mrs. John did not expect Sister Leema this evening, she sighs with relief upon seeing her, greets her warmly and thanks her profusely for stopping by and watching over Jini. Sister Leema knows the John family well and an unannounced visit from her surprises neither Mrs. John nor her granddaughter. For the past seven years, Sister Leema has visited the household regularly.

“When times are toughest,” says Mary John, “I turn to the sisters for help.”

For more than a decade, the Nirmala Dasi Sisters have served as a safety net for Mrs. John and her family. When she wanted to start her own street vending business after her husband’s death, the sisters provided the initial financial backing. They then helped cover the costs of building her current concrete home, which replaced a flimsy mud hut. With funds they raised from German donors, the sisters also pay the tuition for Jini to attend the nearby convent school as well as for her older brother to study engineering.

Despite her father’s recent death, and thanks to the loving support of her family and the Nirmala Dasi Sisters, Jini is well adjusted and excels at school. The hopeful and enthusiastic girl still entertains dreams of an exciting, adventurous future.

“I want to be a pilot,” she beams to Sister Leema, who sits beside her on the dimly lit concrete floor and helps her with her homework.

In 1971, Syro–Malabar Catholic Archbishop Joseph Kundukulam of Trichur, Kerala, founded the Society of Nirmala Dasi Sisters with a mission to care for society’s destitute, abandoned and marginalized. Today, its 265 sisters operate more than 30 homes, centers and clinics that serve impoverished communities, orphaned children, the elderly, the mentally and physically disabled, single mothers and their children, substance abusers, persons with H.I.V./AIDS and persons affected by Hansen’s disease. Though the sisters primarily work in Kerala, they also run facilities in other states in India as well as overseas, in Hungary and Kenya.

In 1989, Mumbai’s Syro–Malabar church leaders invited the Nirmala Dasi Sisters to minister and provide basic social services to the impoverished residents of Dharavi.

“They had great experience in this field and a very good name,” explains Father Francis Eluvathingal, chancellor of the Mumbai–based Eparchy of Kalyan. “So they were chosen for this work by the eparchy.”

Since their arrival in Dharavi, the Nirmala Dasi Sisters have disappointed no one, quickly becoming leaders within the local church and a lifeline for Dharavi’s residents.

“When we first decided to offer social services in Mumbai, we trusted God’s providence that we’d go the right way,” recalls Father Juston Kallely, pastor of St. Sebastian Church in Dharavi. A small parish with only 52 families, it is the only Syro–Malabar Catholic congregation in the area.

“The sisters have been in Dharavi for over 20 years. Their commitment has never wavered. And from that, we as an eparchy have gained confidence and expanded our social services throughout Mumbai. It’s worked out well and has been an excellent boost to the eparchy. We never got enmity from anyone.

“And we’ve learned a lot of things from them — involvement in the community, simplicity, commitment. They get up and do it,” adds the priest.

Five days a week, the sisters operate a nursery school and day care center that enrolls more than 60 children with working parents. The center offers meals and a structured program of educational activities. It has earned a reputation as the best day care provider around; even Dharavi’s more affluent families clamor to register their children on its long waiting list.

Two afternoons a week, Nirmala Dasi Sisters also run the Dharavi Dispensary, a free walk–in health clinic that attracts a regular line of residents. Many families in the area, such as the John family, depend on the dispensary for their health care needs. Two volunteer doctors examine patients; the sisters distribute medications and other volunteers help out with the administration.

On other days and in the evenings, the sisters regularly visit families, whether to help care for an elderly or seriously ill family member, baby–sit or give advice.

“It’s a blessing from the Lord to work with the poor and needy,” explains Sister Lovely Kattumattam, who worked in Dharavi for seven years. She now works at a new Syro–Malabar Catholic social service facility in a different Mumbai suburb.

“People in Dharavi are not well mannered or cultured. They have their disagreements and fights. But the sisters work for peace, fellowship and love. We live there in the same simple facilities. We have a happy life despite shortages and the respect of the community because we’ve opted to live without.”

The high standing in the community the sisters enjoy today, however, did not come easily.

“When they first began here in Dharavi — a Hindu and Muslim area — to see a sister at that time was something odd,” explains Jancy Kuthoor, a bright–eyed 28–year–old Dharavi resident and an active member of St. Sebastian parish and volunteer at the Dharavi Dispensary. “They were just three sisters in a small home. It was difficult to begin here since there wasn’t a Syro–Malabar parish back then. Initially, people were not that into it. But, they did sincere work and people took note. Now people are into it. The parishioners and the priests have gotten involved. The sisters have taught us, ‘I’m there for you. You’re there for me.’ ”

The pioneering sisters faced other challenges. Though still one of India’s most impoverished, polluted and overcrowded communities, Dharavi in the late 20th century was far worse.

“It was a real miserable situation in Dharavi,” recalls Sister Lovely. “People lived in very small, overcrowded shacks with almost nothing. If it rained, everything went under water. But slowly, things have improved.”

“In those days, Dharavi was a slum,” explains Ms. Kuthoor. “It was just a marshy land, but people wanted to make it a place worth living. At that time, they weren’t earning enough that they could build nice houses. First it was a cloth tent, then a mud hut, then some stone. What started as temporary became permanent.”

Until as late as the 1950’s, Dharavi was rural marshland. Residents from nearby villages harvested the many fish that populated its mangrove swamps.

“The water was so clear, you could see the fish,” says Father Lancy Pinto from the bell tower of the Latin Catholic St. Anthony Church, which overlooks Dharavi’s expanse of rooftops. The pastor of St. Anthony’s 7,500–person parish, he first came to Dharavi as a young seminarian in 1987 to work at a local orphanage.

As countless new factories and corporations sprouted up in Mumbai, waves of professionals and laborers from all over the country flooded the city in search of a better life.

“Mumbai was like the hen that laid the golden egg, and still is,” says Ms. Kuthoor. “There is work for each and everyone. Ah, but you have to leave your ego aside. You can’t say, ‘Goodbye, I can’t do this job. It’s below me.’ To say that, then there’s no work for you here. But if you come with the thought that I have to make my living here, it’s the best place. My father came here 40 years ago from Kerala. He was educated, but he didn’t get a job according to his education. He did some menial jobs so he could survive.

“To survive here, you have to fight,” she adds.

The poorest newcomers soon began squatting in the undesirable marshes of nearby Dharavi. By the 1970’s, it was teeming with migrants from all reaches of the Indian subcontinent.

“You see all of India in Dharavi. All regions of the country are represented here,” says Father Pinto. Indeed, potters from Gujarat have created their own local guild. Skilled tanners from Tamil dominate the local tanneries. And artisanal embroiderers from Uttar Pradesh have helped develop the flourishing local garment industry.

“The area was originally government property, but the government never said anything about the squatters,” explains Father Pinto. “That’s how Dharavi expanded. Nothing was planned, like much of Mumbai. There were no maps. It was totally the people’s effort.

“You can no longer say Dharavi is a slum,” declares Father Pinto. Though he readily acknowledges its many social and economic challenges, he has witnessed and helped bring about many improvements over the years and is proud of where he lives.

“We’re established now,” he continues. “Mumbai’s new migrants can’t afford to live here. You don’t find kids playing in mud. We have developed lanes and gutters. We have strong, raised, brick houses; not huts that flood. And Dharavi’s youth have gone on to become engineers, architects, doctors and teachers. Over the last 25 years, real change has been happening.”

Though thrilled that Dharavi has come into its own, he and other local leaders worry — and for good reason — the neighborhood may fall victim to its own success. Today, Dharavi sits smack in the heart of modern–day Mumbai and offers easy access to three railway lines and all major highways, which connect it to any part of the city. An ever–more cramped and tall skyline of modern, high–rise buildings now encircles Dharavi’s small acreage of mostly one– and two–story homes and factories.

In recent years, property values near and in Dharavi have skyrocketed. And as Mumbai continues to grow at an almost exponential rate (the McKinsey Global Institute Report forecasts the metro area’s population will reach 33 million by 2030), stakeholders on all sides predict the values will soar ever higher in the future.

Already, local authorities, under pressure from powerful developers, are planning a large–scale development project for the area. Ironically, Dharavi’s now international notoriety as India’s worst slum has only intensified efforts to reclaim and gentrify the squatted government land.

In response, Father Pinto and other leaders have begun mobilizing the community, informing its members of their rights and advocating on their behalf. Though Father Pinto senses he faces an uphill battle, he refuses to stand by quietly and watch his parishioners, friends and neighbors forcibly displaced from or priced out of their homes.

“In 25 years,” the priest sighs despondently, “you’ll find a different face on Dharavi.”

Whatever the future holds for Dharavi and its residents, one thing remains certain: the Nirmala Dasi Sisters will continue to serve Mumbai’s destitute, abandoned and marginalized.

Most recently, the sisters have taken charge of a new Syro–Malabar Catholic facility in another town on Mumbai’s outskirts, which includes the Ashraya home for the elderly and the Anugraha home for children. Both houses provide for all the needs of their residents.

In 2008, the 53–bed Ashraya home opened its doors to Mumbai’s needy and abandoned elderly. Last year, the Anugraha home for children welcomed its inaugural group — 11 boys and four girls, ages 6 to 13 — all of whom come from families affected by H.I.V./AIDS. Still under construction, the Anugraha home will accommodate more children once complete.

As the sun sets on the facility, Kirti Lawrence, a 72–year–old Ashraya resident, makes her way across the grounds to the Anugraha home for children, reading glasses and teaching materials in hand. A widow whose only son suffers from schizophrenia and with no close relatives, she moved into the Anugraha home when it opened three years ago.

As a retired schoolteacher, Mrs. Lawrence has made it her job to tutor the youngsters at the Anugraha home.

Along the footpath, she waves to Sister Shainty Rose, who tends to a small rose garden. Hunched on either side of the sister, two boys — Anugraha residents — help out with their nimble fingers.

As Mrs. Lawrence reaches the children’s home, three girls stop to greet her, their attentive eyes meet hers, eager to impress.

Mrs. Lawrence points to one of the girls. “When she arrived, she had a blank stare,” recalls the septuagenarian. “Her growth was stunted. She was 12 years old and so tiny. Look at her now.”

Mrs. Lawrence enters the study hall, the children settle down and the lesson begins. She helps the group with all their subjects in school: English, mathematics, geography and civics.

First though, she gestures to the children and they quickly rise to their feet. She begins a prayer. A few moments into it, the electricity cuts off — as it often does several times a day in this poor, underserved neighborhood. Accustomed to the annoyance, Mrs. Lawrence flips on the switch of a battery–powered floodlight in the room; the prayer and tutorial continue uninterrupted.

Strolling through the hall, Sister Lovely stops at the study hall door for a moment and peeks in. She relishes what she sees: The children have found a mentor in Mrs. Lawrence, and she a new sense of purpose in the children.

“It’s total chaos in Dharavi,” says Sister Lovely, thinking back on her seven years in the impoverished neighborhood. “This is quiet. You can do your work with no problem. But wherever we work, we work for the Lord.”

Award–winning journalist Peter Lemieux reports from Africa and India for ONE.