faces many challenges in maintaining that record, from new delhi, liddy dutt reports. >> this doctor has been treating patients with polio for 30 years. a national campaign to vaccinated hundreds of millions of indian children against the disease is likely to lessen the doctor's future caseload. >> now because the prevalence has gone down, i see older and older patients coming to me. there is a huge backlog out there but they are still there. but we feel happy that i don't have to be with a freshly paralyzed case of poliomyelitis. >> poor sanitation, bad water quality, and a large number of people living in small spaces once constituted a perfect breeding ground for the disease. but greater public awareness and good project management mean health workers haven't reported a polio case here in years. >> the success of india is the greatest shorten for the pole yo initiative. because if india had stumbled over the last couple of years, last three years, any time during the last three years the word would have been completely discouraged. >> this thing may be a part of the past, but indi