With the most extensive immunization process in the world, India is ready to declare itself polio-free after three years without the disease.

According to the Reuters, Monday marks the three-year anniversary of India's last recorded case of polio, a two-year-old in West Bengal. Now that three years have passed, the India may be declared polio-free.

India is the latest in a series of efforts to stamp out polio worldwide and the disease now only exists in Nigeria, Pakistan and Afghanistan, the World Health Organization (WHO) said.

"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 Reuters.

Certification and the legal process to be declared polio-free is expected to take three months and could be officially announced by the end of March. Since the 50s, polio has been most prevalent in countries with poor sanitation because it is highly contagious and spreads from person to person easily.

For this reason, countries like India struggled long and hard to rid themselves of the disease, which is known to cause irreversible paralysis within hours. Young children were the most vulnerable to the disease and were the highest priority in the population-wide vaccination.

As recently as 2009, India had 741 cases of polio, which the Global Polio Eradication Initiative told BBC News was the most in the world. Given the country's dense population, poor sanitation, inaccessible terrain high birth rate and reluctance to accept the vaccine, India's accomplishment is highly impressive.

"Despite these obstacles, India proved to the world how to conquer this disease: through the strong commitment of the government, seamless partnership comprising the government, Rotary clubs, WHO and Unicef, and above all the tireless hard work of millions of front-line workers - vaccinators, social mobilisers and community and health workers - who continue to implement innovative strategies to rid India of polio," Nicole Deutsch, head of polio operations in India for UN children's charity Unicef, told BBC News.

India's aggressive immunization campaign focused on sanitation as well as convincing Muslim community members to participate and let their children be immunized. Health officials attacked the worst areas known for polio first and also gave vaccinations at dozens of transit locations, targeting migrant workers.

"India needs to stay extremely vigilant and continue its efforts to ensure that the children remain protected against polio, until the disease is eradicated globally," said Deutsch. "India plans six polio campaigns in 2014 and 2015. In each campaign, 2.3 million vaccinators will immunize nearly 172 million children."