India has marked three years since its last case of polio was reported. This is regarded as a major milestone for a country that until recently accounted for most of the world's cases of the disease.
The Indian government announced on Monday that the country has been polio-free for three years, which is the period of time needed without a reported case for the World Health Organization (WHO) to consider a country to be free of a disease.
Once the organization officially confirms the data, it will formally certify India polio-free.
Health Ministry spokeswoman Manisha Verma said the achievement was due to a massive immunization program that involved some 2.5 million volunteers and medical workers.
"Proud day for all of us as Indians," Junior Home Minister RPN Singh wrote on Twitter. "India is polio-free for three years."
"India was once thought to be the most difficult country in which to achieve polio eradication," the Global Polio Eradication Initiative, which is spearheaded by the WHO, said in a statement.
In 2009, India reported 741 polio infections, which accounted for nearly half the world's total. But by 2010, due to the massive vaccination program, the number of reported cases dropped to 42.
Polio is a preventable disease that usually infects children under age 5 after they drink contaminated water. The disease attacks the central nervous system causing permanent paralysis, muscular atrophy or death. It has been eradicated in most countries however the disease remains officially endemic in Pakistan, Afghanistan and Nigeria.
Despite the anniversary, health officials remain concerned about the possibility of polio entering the country from neighboring Pakistan.
To prevent a reintroduction of the virus, Indian health authorities have set up polio immunization booths at the two border crossings with Pakistan and all children who enter by road and train are being given vaccines.
New Delhi also recently announced that travelers from Pakistan must show proof that they have received the oral polio vaccine at least six weeks ahead of their travel to India.
hc/pfd (AFP, AP, dpa)