Through the heaving crowd of a Delhi railway platform, Vandana Saini spots a sleeping toddler slumped on her mother's shoulder. She darts forward brandishing a tiny squeeze bottle. "Polio?" she hollers over the screech of train brakes, inspecting the baby's fingernail for the tell-tale ink mark that shows the recently vaccinated. The mother shrinks back for a moment, then recognizes Ms. Saini's yellow vest, the sign of India's 2.3-million volunteer vaccinators. She nods assent and tips the baby's head off her shoulder. As the crowd eddies around them, Ms. Saini expertly squeezes the baby's cheeks until her mouth opens, deposits two drops of vaccine, marks the fingernail and sends the family onward, pivoting on her heel to spot the next child.
She will squeeze and drop, squeeze and drop each day this week, as she has tens of thousands of times before in her 10 years of working with India's polio eradication effort. She patrols the platforms and she rides the trains, working her way from car to car until she has done all the children, then disembarks and gets started on the next train back - seven or eight trains in a day.
This way, the polio team hopes, she will catch impoverished economic migrants flooding into the city. They come from villages with no sanitation to slums with no sanitation and they are most likely to carry the virus and be missed in a door-to-door campaign. An army of volunteers is at work this week at every rail station, every bus depot, every major crossroad outside the megacities; they aim to inoculate 174 million children.
The train-station campaigns are an Indian innovation, one of several new approaches that have helped to get this country achingly close to a goal that has seemed, for years, unobtainable.
Polio is all but gone from India, from this gigantic nation that has been the source for most of the critical new outbreaks in recent years, its last stand winnowed down to just two or three areas no bigger than 30 square kilometres.
"We have it on the ropes," said Bruce Aylward, the Canadian who has directed the World Health Organization's global polio eradication program for more than a decade.
Yet India's moment has gone unnoticed by a world bored with the "this-close" narrative of polio. This has critical implications: The fight against polio is all but bankrupt - short of $720-million (all figures U.S.) for 2011-12, despite hearty promises from G8 countries to keep the effort well-funded to the end.
A high-powered partnership has formed around polio eradication in recent years, its great new champion software tycoon Bill Gates, who calls this ambition his "number one priority" and whose foundation has put in $760-million in the last three years. And the WHO, UNICEF and Rotary International are equally engaged. India itself injects $300-million a year into the fight. But without the cash to continue, the partnership will have to curtail efforts to boost coverage.
Dr. Aylward and other experts understand the donor frustration - year after year, polio cases decline in some countries, but swell in others, while the overall cost of the campaign nears $10-billion. "The program seemed to stall on the precipice of eradication," said Hamid Jafari, the director of the WHO's India team.
But the experts have a worry of their own: this time, it really is different. India has had just one polio case in 2011, and only six in the past six months. And if it's possible here, "You can do it anywhere," Dr. Jafari said.
India's fight against polio holds two lessons for the rest of the world: the first concerns the perils of getting close to wiping out the virus, but not all the way there - and the second, the progress that is possible with a combination of political will, a healthy budget and scientific and social innovation. The poliomyelitis virus, which can cause life-threatening paralysis in just hours, was once a global scourge.