Moradabad is a nondescript and scruffy city, 110 miles north of the Indian capital Delhi. Few have heard of it, despite its population of nearly five million. But it is about to become the site of an astonishing victory against a terrible disease.

Moradabad has long been the centre of one of the most stubborn concentrations of polio in India.

The disease is passed on by person-to-person contact and, with Moradabad's poor inhabitants frequently travelling far across the country in search of work, outbreaks elsewhere have often been traced back to the city.

The World Health Organisation (WHO) stipulates that three years must pass without any cases of polio occurring before a region can be declared polio-free.

Moradabad, which only recently had 60-80 cases a year, is expected to qualify in 2012.

"This will be a wonderful thing – for us, for India, for the people of Moradabad," said Dr Mohammed Arif, a public health specialist and organiser of anti-polio campaigns in the area.

There is a bigger national milestone on the horizon. If in India as a whole there are no more confirmed cases before 13 January, the country will have completed its first year without a new victim.

And if polio is gone from India, the only countries where the disease is still endemic would be Nigeria, Afghanistan and Pakistan.

India's likely achievement would be a big step towards the eradication of a global disease – the second after smallpox, which was officially defeated worldwide in 1979.

"That would really be something to be happy about," said Arif.

It would also be a boost to a global effort which has been flagging in recent years, with key milestones repeatedly missed.

Last year, Sir Liam Donaldson, the UK's former chief medical officer who now chairs the independent monitoring board of the Global Polio Eradication Initiative, said the final success of the eradication campaign, which has seen cases reduced by 99% in 20 years, was "on a knife-edge". In some places, particularly sub-Saharan Africa, polio has even made a comeback.

In India, a mass vaccination campaign involving more than a million volunteers reduced cases nationally by 94% between 2009 and 2010, from 741 to 42, and down to the single case last year.

The success is due to a combination of highly motivated local workers, philanthropy, the involvement of international health bodies and the sometimes inefficient but nonetheless essential support of local government.

Equally important in overcoming the last bastions of the disease, as in many parts of the world, has been the consent of local religious figures.

Over the past decade one of the biggest obstacles to polio eradication in India, as in Pakistan and Nigeria, has been the resistance of poor, largely illiterate Muslim communities such as those in and around Moradabad.

Even as the first campaigns got underway in the area in the late 1990s, local clerics began telling congregations that the vaccinations were part of a government plan, backed by the west, to make Muslim women infertile.

The febrile atmosphere of the early years of the last decade, against a backdrop of the 9/11 attacks and wars in Iraq and Afghanistan, aggravated the problem.

Karula neighbourhood in Moradabad has seen some of the fiercest resistance to the campaign.

A quarter of a million people, many of them small children, are packed into Karula's narrow lanes. With no proper sewage system and monsoon rains flooding streets with faeces, polio – often spread by poor sanitation – was endemic.

Muzaffar Sultan Torabi, a senior cleric in Moradabad, said the local Muslim community "had been upset" by events in the Middle East and Afghanistan and by "western portrayals and blaming of Islam … for their own problems". He added: "They were not trusting scientific medicine and thought immunisation was an American plan to sterilise our girls."

But some religious leaders convinced the community otherwise.

Torabi said that he had attended immunisation clinics in clerical robes to show "that a common Muslim man is able to trust the programme".

He added: "I told them that in nowhere in the Qur'an is it written that we should be unhealthy, or not take care of our hygiene and that if tomorrow our children are suffering from polio then they will not be able to do the prayers properly. Slowly they understood my point."

Noor Jahan, a 60-year-old widow in Karula, said she had once strongly opposed immunisation, believing what "they said in the mosques about the American conspiracy to stop Muslims having children". Since listening to Torabi, she has begun working very actively to tell the doctors about all the new births in the neighbourhood so the babies can be vaccinated.

In Dumghar, a small village seven miles outside Moradabad, weekly consciousness-raising and immunisation clinics are held. Village women line up in the dust of the school playground to hear organisers from the Rotary Club talk about basic hygiene and to have newborns vaccinated. Schoolchildren also queue for a free lunch of rice and beans. This is one of the poorest regions of India with social indicators on a par with those in sub-Saharan Africa.

There are still problems. One health worker told the Guardian that she constantly faced suspicion – even abuse – from fathers who said she was corrupting their daughters.

But the message has got through nonetheless. Mithilesh, 28, had brought her two-month-old daughter, Soni, to be immunised. "I don't listen to anyone saying anything negative. It's good for my child so of course I'll do it," she said.

Fatal five

Smallpox Officially declared eradicated in 1979 after a global vaccination programme led by the World Health Organisation (WHO). The last known natural case was in Somalia in 1977. Since then, the only known cases were caused by a laboratory accident in 1978 in Birmingham, England, which killed one person and caused a limited outbreak.

Polio Cases have fallen by more than 99% since 1988, from an estimated 350,000 to 1,349 in 2010. In 2011, only parts of four countries in the world (Afghanistan, India, Nigeria and Pakistan) remain endemic for the disease – the smallest geographic area in history.

Tuberculosis While mortality rates have fallen by just over a third since 1990, there were 8.8m cases and 1.45 million deaths in 2010. The Stop TB Partnership – a WHO-backed global effort – aims to halve cases and deaths by 2015 and to eliminate the disease by 2050.

Malaria There were 216m cases and an estimated 655,000 deaths in 2010. Mortality rates have fallen by more than 25% globally since 2000. Most deaths occur among children in Africa, where every minute a child dies of malaria, and the disease accounts for approximately 22% of all childhood deaths. The Roll Back Malaria partnership – the global framework coordinating action against the disease – hopes to eradicate it one day, but aims to reduce the incidence of malaria to fewer than 85-125m cases a year by 2015.

HIV/Aids HIV has claimed more than 25 million lives over the past 30 years, but new HIV infections worldwide declined by 17% between 2001 and 2009. There were approximately 34 million people living with HIV in 2010. In November last year, a joint report by the WHO, Unicef and UNAIDS found that increased access to HIV services resulted in a 15% reduction of new infections over the last decade and a 22% drop in Aids-related deaths in the last five years.

Sources: WHO, Stop TB Partnership, Roll Back Malaria Partnership, UNAIDS