India on Monday marked three years since its last reported case of polio, paving the way for it to be declared free of the crippling virus and boosting efforts to wipe out the disease globally, the Organization (WHO) said.
The country's last case of the wild polio virus was detected on Jan 13, 2011, in a two-year-old girl in the state of West Bengal. Three years without any new cases means India can be declared polio-free.
Afghanistan, Pakistan and Nigeria are the only countries in the world where the disease remains endemic.
"We give huge credit to the government... It makes us extremely proud and highly responsible for having helped the government to reach this incredible achievement," India's WHO representative, Nata Menabde, told the Thomson Reuters Foundation.
Menabde said the WHO would officially declare India as polio-free by the end of March, when the legal process for certification was completed.
Until the 1950s, polio crippled thousands every year in rich countries. It attacks the nervous system and can cause irreversible paralysis within hours of infection.
The highly infectious disease often spreads in areas with poor sanitation - a factor that helped it keep a grip on India for many decades - and children under five are the most vulnerable. But it can be prevented by population-wide vaccination.
India had been considered one of the toughest places in the world to eradicate polio. Many families in poor, high-risk states such as Bihar and Uttar Pradesh migrate for work, while other communities live in remote or inaccessible areas.
Menabde said millions were involved in the drive to immunize children by giving them polio drops.
They targeted migrant families at bus stations, on trains, at construction sites, and at local festivals. Some used motorcycles or trekked by foot to reach remote villages.
As a consequence, over 170 million children are immunized every year, with millions more targeted on house-to-house visits. The drive has cost the government $2.5 billion since 1995.
In 2009, 741 Indians fell sick with polio, nearly half the world's cases that year. The number dropped to 42 in 2010 and only one in 2011.
India's success has given impetus to the global fight against polio, Menabde said.
"While the whole global eradication was stagnating, India has been the rescuer of this belief that it is possible," she said. "Polio eradication is a very costly operation and so donors and partners were losing hope and patience. Now they are all very actively mobilized into channeling their efforts."
There were 148 cases of polio in Afghanistan, Nigeria and Pakistan in 2013, while 224 new cases were detected in non-endemic countries such as Somalia, Syria and Kenya.
These countries face a range of challenges such as violent conflicts, weak health systems and poor sanitation. In Pakistan, gunmen frequently attack polio vaccination workers, accusing them of being Western spies and part of a plot to sterilize Muslims.