After a firefighter rescued her, the girl described a life akin to slavery, child welfare officials said. Her uncle had sold her to a job placement agency, which sold her to the couple, both doctors. The girl was paid nothing. She said the couple barely fed her and beat her if her work did not meet expectations. She said they used closed-circuit cameras to make certain she did not take extra food.
In India, reported to have more child laborers than any other country in the world, child labor and trafficking are often considered symptoms of poverty: desperately poor families sell their children for work, and some end up as prostitutes or manual laborers.
But the case last week of the 13-year-old maid is a reminder that the exploitation of children is also a symptom of India's rising wealth, as the country's growing middle class has created a surging demand for domestic workers, jobs often filled by children.
The Indian news media, usually a bullhorn for middle-class interests, ran outraged front-page articles. But the case was hardly unique. Last week, an 11-year-old Nepalese girl, working as a servant, said that her employer had beaten her with a rolling pin, according to the police.
Indian law offers limited safeguards and limited enforcement to protect such children, and public attitudes are usually permissive in a society where even in the lowest rungs of the middle class, families often have at least one live-in servant.
"There is a huge, huge demand," said Ravi Kant, a lawyer with Shakti Vahini, a nonprofit group that combats child trafficking. "The demand is so huge that the government is tending toward regulation rather than saying our children should not work but should be in school."
The International Labor Organization has found that India has 12.6 million laborers between the ages of 5 and 14, with roughly 20 percent working as domestic help. Other groups place the figure at 45 million or higher. Unicef has said India has more child laborers than any other country in the world.
Many of these children come from India's poorest states, either through shadowy job placement agencies or by kidnapping. In 2011, more than 32,000 children were reported missing in India, according to government crime statistics.
Mala Bhandari, who runs Childline, a government hot line for child workers, said India's urbanization and the rise of two-income families were driving demand for domestic help. Children are cheaper and more pliant than adults; Ms. Bhandari said a family might pay a child servant only $40 a month, less than half the wage commonly paid to an adult, if such servants are paid at all.
Indian law deems anyone younger than 18 a minor. But the Juvenile Justice Act of 2000 also creates a loophole: Children between 14 and 18 are allowed to work a maximum of six hours a day in nonhazardous work. Children younger than 14 are prohibited from working as servants, a statute that is widely flouted. Employers are required to provide daily education and document the child's daily break hours, though most families ignore such requirements because enforcement is largely nil.
"What happens within the four walls of a home, nobody knows," said Ms. Bhandari, who contended that while abuse was not the norm, it was not rare.
Domestic work employs millions of people in India, most of them adults. India's rich often have a retinue of servants, drivers and other helpers. Mukesh Ambani, the billionaire industrialist, reportedly has several hundred domestic workers in his skyscraper residence in Mumbai, the country's financial capital, with some of his servants trained by one of India's elite hotels. Some Indian families living abroad also take a servant; last month, an Indian maid in New York won a $1.5 million judgment against an Indian diplomat and her husband for abusive treatment.
Societal attitudes toward servants are often shaped by ingrained mores about caste and class. Many servants, especially children, come from poor families among the lower Hindu castes or tribal groups, often from poor states like Jharkhand, Chhattisgarh and West Bengal.
Santosh Desai, a columnist for The Times of India, the country's largest-circulation English-language newspaper, warned in February that India's upper and middle class were growing flabby and indolent through their dependence on cheap household help, and that they also wrongly held "an implicit belief in possessing an intrinsic superiority, an assumed right to lord it over someone lesser."
"As a child nobody dreams of growing up one day and driving somebody else's children to school or washing their clothes," he wrote.
The middle-class families in the housing complex where the 13-year-old girl worked, in the suburb of Dwarka, professed shock over her treatment. Originally from Jharkhand, the girl is now being cared for at a government-run shelter for women. After she was rescued, she was interviewed by counselors with Shakti Vahini, the nonprofit group. They said she told them she had also been required to clean the couple's medical clinic.
They said she also told them of other abuses: On some occasions, the couple reviewed footage from the cameras in the apartment and beat her if they found behavior that displeased them. She said she was provided with two chapatis, pieces of flat bread, as her daily meal. Earlier in the week, the police said they had not yet been able to confirm the presence of cameras in the apartment.
Raj Mangal Prasad, a children's welfare official in New Delhi, said the government was not staffed to carry out raids to look for illegal servants. But if it were, Mr. Prasad estimated, several thousand cases would probably be discovered throughout the capital. He estimated that one household out of 20 employed an under-age servant. "It's plain for everyone to see," he said.
The girl's employers, identified by the police as Dr. Sanjay Verma and Dr. Sumita Verma, were arrested Wednesday after their return to India and remanded to police custody. The police have filed preliminary charges of violations of the Juvenile Justice Act, the Child Labor Prohibition and Regulation Act and other violations of the criminal code.
Their lawyer denied the charges at a bail hearing.
But Mr. Kant, the lawyer with Shakti Vahini, said the courts rarely issued harsh judgments in cases involving the rights of domestic help.
"There is a general feeling that we need these people," Mr. Kant said. "Cases aren't taken so seriously. There is no fear of the law."
Nikhila Gill contributed reporting.
© 2012, The New York Times News Service