For a long time, customers have come to shop at Prem Neelkanth's corner grocery store in a sprawling Bombay slum, buying eggs, bread, tea and sugar. But in the last two years, sickly men and women, some coughing painfully, have also lined up to obtain their tuberculosis medicine.

Neelkanth, 36, is a volunteer in the government's effort to supervise tuberculosis patients as they take their medication. He is one of an army of health workers and neighborhood participants in a federal program known as DOTS, Directly Observed Treatment -- Short Course, funded by a $142 million World Bank loan.

The Indian program, one of 150 around the world, has grown fortyfold since 1998, the fastest-expanding DOTS operation anywhere, covering 890 million people, officials said. Last year, India added 900,000 TB patients under the DOTS program, more than any other country. Health officials estimate that 1,000 Indians die of tuberculosis every day. One in four carry the TB bacillus. An estimated 1.8 million Indians develop the disease every year, of whom 800,000 are infectious, the highest incidence in the world.

Neelkanth's grocery stands near a row of overcrowded shacks, with narrow alleys of open sewers and piles of putrid garbage -- a veritable breeding ground for the infectious, airborne disease.

The TB patients he sees are daily laborers who live nearby and do not have time to make three trips a week to the hospital for six months to receive their required dosages. So on their way to work, they just make a quick stop at the grocer's.

"My grocery shop is now like a TB clinic," said Neelkanth, pointing to a neat row of medicine boxes marked with patient names, given to him by the city's health officers.

"I know everyone in this neighborhood. So if someone does not turn up for their dosage, I go and knock on their door in the night with the medicines. It is my duty to ensure they don't miss a single dose," he said, watching a 50-year-old cart-puller gulp six pills.

Sunita Singh, the TB program's team leader at the World Bank in New Delhi, said that India's tuberculosis control system "is one of India's biggest public health success stories in the past five years.

"It is the story of ordinary people achieving the extraordinary," he said. "It has turned thousands of cobblers, grocers, roadside tea-stall owners and postmen into DOTS providers."

Despite strides in the TB battle, the program is beset by the challenges of a growing HIV epidemic, in which many sufferers contract both diseases. At least 5.1 million people have HIV in India, more than in any other country except for South Africa. Health officials estimate that about 60 percent of the HIV-infected will also contract tuberculosis.

"We are very worried that HIV will worsen the TB epidemic in India," said Lakhbir Singh Chauhan, chief of India's TB program in the Health Ministry.

The government has begun to integrate its HIV and TB programs by opening joint counseling and testing centers. Singh said "both the diseases suffer from acute social stigma in India."

Stopping the intensive TB dosages midway through the six- to nine-month treatment period heightens the risk of developing the multi-drug resistant strain of the disease, a major global threat, according to the World Health Organization. India's default rate is about 8 percent. Last week, the Indian government announced that scientists had discovered a drug that is likely to reduce treatment time for tuberculosis to only two months, and could also counter the threat of multi-drug resistant strains of the disease. However, the drug has yet to undergo three phases of clinical trials on people.

Many of those suffering from the disease are rejected by their families and relatives every year, according to the Health Ministry. Health workers said that some patients meet them stealthily by street corners to swallow the medicines, and ask the workers not to visit their homes. Ishwar Jogdand, 50, a frail man, said he lost his job as a laborer at a construction site after missing many days of work because of his TB. Then his family of six, living in a one-room hut in a slum, turned him away.

For the past six months, he has been sleeping under a highway overpass. "My family said I could return only when I am fully cured," Jogdand said. A health worker from Alert India, a group that works among TB patients in New Bombay slums, visits him every other day to hand over his medication.

Alert India officials said another challenge in administering medicine involves keeping up with workers who change job sites.

"It is quite common for the villagers to come to the city during dry summer months in search of work and return to their village during the rains for the sowing crops," said Geetha Balasubramanian of Alert India. "Some even give false addresses of their village homes to avoid the stigma. So we try to convince the patients not to leave until they complete the six-month treatment and are cured."

Some critics challenge the success claimed by the DOTS program, saying that participants are only the most likely candidates to follow through.

"There are rules about who you register under DOTS. Only after showing the proof of a stable residence and commitment to complete the treatment is a patient taken on DOTS," said Ritu Priya Mehrotra, professor of social medicine and community health at New Delhi's Jawaharlal Nehru University.

"This means the migrant worker, the poorest of the poor who shifts every month from one place to another, is not put on DOTS at all. . . . And they are the ones who need treatment the most."

Prem Neelkanth, 36, hands tuberculosis medicine to a patient at his grocery store in New Bombay. Neelkanth keeps a neat row of medicine boxes marked with patient names and visits the homes of those who fail to show up.