Fighting against this odd is an army of people backed by hundreds of millions of dollars from the world's deepest philanthropies pockets - The Bill and Melinda Gates Foundation.
Known as "Ahavan" - a Sanskrit word meaning "call to action", The foundation's AIDS prevention effort in India, - has a $200 million five-year grant to operate an HIV prevention program on a scale never done before. But in a country as vast as India, it could do with more.
The fight against the deadly disease could very easily cost anywhere up to $1.5 billion a year, said Ashok Alexander, the foundation's India director, citing recent U.S. government figures.
The challenges faced by the foundation is quite complex in a nation as big as India. Often the sex trade - a main transmission route for AIDS - is nearly invisible, with prostitutes working out of truck stops, or even in small village homes. Some sex workers are highly mobile, moving from city to city.
The nation has multiple identities, with each region with its specific set of challenges, such as one of India's hardest-hit areas, its remote northeast. There, most HIV transmissions come from needles shared by thousands of heroin addicts, a problem fueled by the region's proximity to the poppy fields of the Golden Triangle.
Logistics can also be nightmarish in rural areas that often lack basic infrastructure. All these problems are confounded by the stigma attached to AIDS in a very conservative country.
Ahavan's strategy, also one of it's biggest strengths has been to adopt a business-style structure. The product is prevention, and the foundation formed a pyramid structure to get it to consumers. It contracted 15 other organizations that, in turn, work with about 150 grass-roots groups. They employ some 5,000 prostitutes, many of them HIV-positive, to get the message out.
"I talk to women about condoms and how they must insist even their regular clients wear condoms," said Vijaymala, a fruit seller who supplements her income by working as a prostitute without her family's knowledge.
She has a third job working as a "peer counselor" at "Saathi" , a tiny Gates-funded clinic nestled among the shantytown brothels in Turbhe, an industrial area on Bombay's outskirts.
Employing prostitutes means feedback comes quickly when there are problems. "In talking with sex workers, our team found that the women felt the condoms available in the market did not suit them," said Sanjeev Gaikwad of Family Health International, which runs the "Saathi" clinic.
So they went to a condom manufacturer to produce the stronger, better-lubricated ones they now distribute.
Alexander said that after three years of work, it's too soon to evaluate how successful Ahavan has been, but he is positive. "We started off with a five-year grant, but I think we will be here as long as it takes," he said.
