KARACHI, PAKISTAN -- Riaz Uddin remembers that terrible day in 1965 when a truck careening through the crowded streets of Karachi hit his 10-year-old sister Zubida and crushed the life from her.

He remembers standing over her helplessly because there seemed to be no one in a city of millions who would come to take away the body -- no ambulances, no officials, no one.

Then, as word of the accident spread through the slums, a small man came in a white truck crudely fitted as an ambulance, lifted Zubida's body and took it away to be washed and wrapped in white Moslem burial cloth.

"My sister was crushed. I saw her on the street, and no one was there to pick her up. I always will remember that. Edhi had only one ambulance then, but he rushed to her. That is when I decided I would work with him," Riaz said as he carefully cradled a young retarded boy in his arms.

Today, more than 20 years later, Abdul Sattar Edhi has 175 ambulances, and Riaz Uddin oversees an orphanage and home for retarded boys. Both are part of an extraordinary volunteer social service effort built by Ehdi that has bypassed the woefully inadequate and often corrupt public system while touching, and probably saving, the lives of hundreds of thousands of people here in Pakistan's largest city and beyond.

Edhi and his wife, Bilqis Edhi, have become known as Karachi's "angels of mercy."

When hijackers of a Pan Am jetliner opened fire on its passengers at Karachi airport a year ago, it was Edhi and his fleet of small, converted trucks that rushed onto the runway, lights flashing and sirens wailing, even before the shooting stopped. Many died that night, but, had it not been for Edhi and his volunteers, many more would have.

When a runaway child is found by Karachi's police, it is to Edhi and Bilqis that they turn for shelter.

When a young woman, pregnant and battered by her husband, is thrown out of the house, it is to the Edhis that she turns.

And when a destitute man or woman dies and there is no one to bathe and bury the body, it is Edhi and his helpers who do.

While Pakistani officials are proud of the fact that their country cares for an estimated 3 million Afghan refugees, they do not speak as openly of a public social service system that is virtually nonexistent when compared with the need.

Karachi, a city of more than 7 million, has no functioning public ambulance service. Its three city hospitals often have inadequate or nonexistent medical supplies. Regular hospital blood banks often stand shuttered and empty while a few feet away medical students, out of exasperation, run their own blood-gathering facilities and laboratories.

Orphanages, homes for the aged and retarded, local medical clinics for the vast part of the population that is desperately poor, basic help for the destitute -- all are pitifully inadequate here, if they exist at all. Islamic societies and private groups have tried to help, but the need ultimately seems to fall prey to the greed and corruption that by universal acknowledgement dominate public life here.

It is against this tide that the Edhis swim with single-minded determination. Taking contributions as small as a few rupees, a couple of items of clothes or a goat and as large as half a million rupees or the bequest of an estate, they have built a service organization without parallel in this nation of 100 million, and probably matched by few anywhere in the world.

A Maternity Center for the Downtrodden

Julie knows what the Edhis do for the downtrodden of Karachi. She had tried to run away from the beatings and abuse before, but with the help of police, she says, her husband had forced her back. One of his previous wives had killed herself by immolation. Two others had divorced him to escape, and one had run away to Bangladesh. Julie was six months pregnant when she had had enough and, with her two other children, left the house.

Julie went first to Apna Ghar (Our Home), a center run by the Edhis for runaways, the destitute and others with no place to go. When it was time for her to deliver her child, she went to their maternity clinic, part of a complex of free medical facilities in the heart of old Karachi.

There, her child was one of more than 70 to be born in the first week of December. The surroundings were spartan but clean, and the midwives were efficient. All of them were young women who had come to the Edhis for help and subsequently were trained as nurses.

The staff at the maternity center wanted her to stay for a few days to recover her strength, but she was worried about her other two children. So a day after giving birth, she brought her family to yet another Edhi center in northern Karachi. Soon the complex in which she is now housed will contain dormitories, training facilities and recreation areas for 2,000 women.

She is charged nothing for all of this help.

"I don't have any parents. I have three sisters but when I went to them, my husband would come after me. Finally, I thought there was no other place to go, so I came here. At least here they will raise my children properly. What can I do outside?" she asked as she held her newborn child.

As the drama of Julie's childbirth was playing itself out in one part of the complex that makes up the Edhis' main medical center, another was taking place a few rooms away.

Only hours before, a baby had been brought in to the center.

"Come upstairs and see my children," said Bilqis Edhi with the boundless enthusiasm that she displays whether she is holding a newborn child or talking tenderly to an elderly retarded woman.

Her "children" were two babies, one of whom she believed to be only a day old.

"Paro's father cried when he left her here, but the mother was seriously mentally ill and left home. He just couldn't cope," Bilqis Edhi said of a bright-eyed, 10-month-old girl.

Paro hopefully will go back to her family when they can once again manage, but for a baby abandoned outside one of the Edhi centers the night before, there is no such hope.

The baby had been placed in a cradle outside one of the ambulance centers. Outside all the centers are permanent cradles that carry signs pleading with those who might want to abandon a child to place it there rather than let it die.

Over the years, more than 90 children have been left in the cradles and hundreds of others rescued from trash heaps, ditches or roadsides.

For many of these children and hundreds born to young women in Edhi clinics, the Edhis have been not only the difference between life and death, but also the providers of new homes.

By late morning, the baby abandoned the night before had been checked by a pediatrician and was being cradled in the arms of its new mother. Like more than 1,000 others, the baby quickly was given to foster parents who desperately wanted a child of their own.

'I Wanted to Do Something'

The angels of mercy, Abdul Sattar Edhi, 55, and Bilqis Edhi, 40, are people with a simple mission in life: to help others who cannot help themselves.

Millions and millions of rupees are in accounts bearing their names, but they live with their four children in the same simple two rooms they occupied when they began their married life. Smiling, joking with each other, constantly at each other's side, theirs is a relationship rarely seen in an Islamic society where men and women usually do not openly share lives, especially in the traditional, nonwesternized part of society in which they are firmly anchored.

"He's a miser," she quips during a ride to a camp for Afghan refugees, where they run a medical clinic and food dispensary.

"No, she's the miser," he retorts with a laugh.

"I like to watch a movie on television sometimes, but he always comes in and turns it off, saying, 'It will ruin you,' " she says with a laugh.

Always smiling, always laughing, the Edhis see misery that would make others cry. For Abdul Sattar Edhi, there seems only to be the satisfaction of helping, and of seeing a pledge fulfilled.

Edhi was a teen-ager when his family came to Karachi from Gujarat in India in 1947, when the subcontinent was partitioned. Shortly afterward, his mother was paralyzed by a crippling disease, and he watched her slowly die as he scoured the city for medicine.

"I started social work because my mother was crippled. I know the feeling of a crippled man. I wanted to do something for these handicapped people. I promised my mother: I can't give you anything, but I pledge my life to the poor and the handicapped," he says.

In 1950, with a few others, he began to serve his own community of Gujeratis. They raised money for a clinic and bought one ambulance.

"I wasn't in a position to pay a driver, so I took on the task myself. Since then I have never sat on the back seat of any of my ambulances," he says.

"I can't give words to the feelings I used to have when I picked up crippled, dirty men and women from the streets of Karachi," he says. "I used to treat them myself, thinking that once again I am being given a chance to serve my mother."

Along the way, a young nurse came to work in the clinic, and the two began working side by side. When he proposed marriage -- a rare event in a society where marriages generally are arranged -- she accepted. "We used to work together just the way we are now, and then one day we decided we should do this together forever," Bilqis Edhi says.

On the afternoon of their marriage, a child fell from a balcony nearby and they stopped the celebration to take it quickly to a hospital, where Edhi remained throughout the night, the first of countless nights spent in hospitals and by telephones, waiting for the next call of distress.

"He sits by the phone, and if it doesn't ring after a few minutes, he thinks there must be something wrong with the line and calls the telephone exchange," Bilqis Edhi says with a smile.

An Outpouring of Funds and Support

With hundreds of volunteers willing to help and millions of rupees in his accounts, Abdul Sattar Edhi still answers the phones and drives to help those in need. Bilqis Edhi still washes the bodies of the dead and wraps them for burial, as she did the night of the Karachi hijacking.

"I still have a picture of the air hostess," she said of Neerja Mishra, the Pan Am stewardess from Bombay killed by the hijackers. "She was so beautiful. All she did was open the door, and the hijacker shot her. I took her to the hospital myself. I washed her and wrapped her. It was because of this girl so many were saved."

Perhaps their success is because of this unstinting personal dedication and example. Perhaps it is because they have touched a wellspring of deeply held Islamic belief in giving and helping that others have been unable to tap. Whatever the cause, the outpouring of funds and support in a city better known for corruption is seemingly unending.

Time and again, from all points on the political and social spectrum, the answer was the same when people were asked about the Edhis: "They are saints."

"If there were a poll today, Abdul Sattar Edhi would be the most respected and popular man in Pakistan," one journalist said.

The votes, in effect, are cast hundreds of times daily in Edhi centers throughout Karachi, as people, many of them far from wealthy, come to give.

Tariq, a young businessman, recently went to the ambulance center in Clifton, a posh Karachi residential area, and quietly gave 350 rupees, $20 in U.S. currency but in local buying power worth about $350. It is something he said he does monthly.

"I am a businessman," he said. "Like my friends, I feel we should give, and there is no other place we know where we are certain they will do right. Once you see somebody working so hard for others, then you come. You trust."

Others give 3 or 10 or 20 rupees. Some give a goat or contribute cooked food or cloth or medicines or even ambulances. Some have given thousands and tens of thousands of rupees. From the government, however, the Edhis will accept no money. Nor will they turn to government workers.

Governments here can never provide genuine social service, Edhi says, adding, "Social work requires complete dedication and honesty. Those working on monthly salaries with retirement programs after 25 years of service can hardly do the work one expects from a volunteer with a pain in the heart for needy persons."

Pakistan's government, in its zeal to cast the country as an Islamic state, has taken over the collection of the traditional Islamic zakat, or welfare tax of 2 1/2 percent. But it is to Edhi, and to a few other organizations such as his, that people turn with true voluntary fervor. Edhi says he now has tens of millions of rupees invested in bonds to ensure the continuation of his operations.

As he gets older and foresees a time when he might no longer be around to run his ambulance fleet and his welfare centers, Edhi's ambitions are growing.

He wants to establish a permanent trust of 250 million rupees. He wants Edhi centers in all of Pakistan's cities. He wants ambulance helicopters to serve the country's horrendously dangerous highways. He wants a ball point pen factory "to be run entirely by the handicapped, the destitute and volunteers."

"I will see to it myself how the trust is to run after the Edhis are dead," he said the other day. At that moment he was seeing to the here and now, by traveling deep into the drought-ravaged Thar desert, where government officials have refused to acknowledge that a problem exists, and where Edhi runs 25 relief centers.

THE EDHI EMPIRE

KARACHI, Pakistan -- Free social service programs sponsored by Abdul Sattar Edhi and Bilqis Edhi have grown markedly in the past several years and now include:

34 ambulance centers in Karachi and 10 other Pakistani cities. More than 175 ambulances are in operation. In Karachi alone, there are approximately 150 calls daily to deal with the dead and between 400 and 500 emergency calls. More than 20,000 unclaimed bodies have been buried during past 22 years.

Nine dispensaries for free medical services in Karachi and four other cities. They include two maternity centers where more than 300 children a month are born. The main clinic includes pediatric care, eye services, a diabetic clinic, family planning services and laboratory facilities. An estimated 100,000 persons are treated yearly.

Three facilities for the mentally retarded, abandoned children and runaway, battered and destitute women. New facilities are under construction. Young women are trained as nurses and midwives; children are placed for adoption; and young men and women are matched for marriage. A ballpoint pen factory is under construction to provide employment opportunities. There also is a rehabilitation center for heroin addicts. An estimated 22,300 missing children and adults have been returned to families.

Special services include medical clinics and food at Afghan refugee camps in Karachi and Peshawar, meat for government hospitals and emergency services and supplies during several national disasters, such as floods and earthquakes.

Estimated contributions, all from public donations, are running at 50 million rupees yearly in cash and goods -- a sum equal to $3 million but closer to $50 million in buying power. An average meal is estimated to cost three rupees (17 cents), and a stipend for a nurse averages about 600 rupees ($35) monthly.