People say you either love India or find its challenges too great. I have been there many times since my first visit more than 30 years ago, and I have grown to love it.

Yet, modern India remains a country of contradictions. It is a place where unimaginable wealth sits alongside acute, life-threatening poverty; strong Indian culture and tradition struggles against fervent westernisation; and whilst renowned for its highly intelligent, well-educated people it has the fifth lowest female literacy rate in the world.

It should perhaps not be surprising then that, as India becomes a growing global economic force, the debate about the aid to India continues to grab headlines, and these past few weeks have been no different.

For me, Amartya Sen - Nobel Prize winning Indian economist - perfectly summed up the danger of misreading a country's economic growth as a sign of prosperity for all: "Even today, after 20 years of rapid growth, India is still one of the poorest countries in the world, something that is often lost sight of, especially by those who enjoy world-class living standards thanks to the inequalities in the income distribution." For Sen, and for me, economics is about far more than GDP - it is about how people live - and die - and how we can all help those in need wherever our help can make a difference.

But in the midst of this increasingly contentious debate has come an extraordinary piece of news that will help defy the opinions of those who believe that aid to India is neither effective nor needed - for the first time in history there is no polio in India.

One of my abiding impressions of that first visit was of paralysed children crawling and begging on the city streets. It is a testament to humanity, solidarity and determination that no more of India's children will have to suffer in that way.

Despite only three years ago being home to the highest number of children affected by polio in the world, this vast country was officially declared free, on 25 February, of this highly contagious, crippling disease.

This achievement is not to be underestimated. The numbers tell you why. Last year alone, 900 million doses of the oral polio vaccine were administered and more than 170 million children under five, most at risk from the disease, were vaccinated in two national campaigns.

UNICEF, along with its partners including DFID, which last year doubled its support to the global eradication campaign, has been working alongside the Indian government to help make this great achievement possible.

And as Bill Gates pointed out when explaining his own foundation's decision to invest heavily in India, it is the leadership of their government that should be credited with the country's success. They have largely funded the eradication campaign and led development of the programme so that it can be sustained within a unique Indian culture. But the job is huge and why would we ask India to cope with it alone when we have a significant contribution to make?

The eradication effort has involved producing micro maps of the huge slum areas, which dominate the edges of the increasingly modern cities - particularly in the two of the country's poorest states of Uttar Pradesh and Bihar - to try and capture every last child. It requires conducting mass immunisation sessions on India's huge train network, as well as stationing vaccinators at borders, in bustling market towns and in migrant settlements.

UNICEF continues to play a vital role in providing the technical expertise and knowledge required to reach every child where millions live in overcrowded slums, with poor sanitation and infrastructure; conditions in which contagious disease like polio thrive.

But as always, India's extraordinary achievement is not the end of the story. Their pending success leaves three countries - Nigeria, Pakistan and Afghanistan - where polio still remains a very real threat to children's lives.

These countries have been hampered by cultural opposition to immunisation programmes, re-infection across borders and ongoing security issues. As in India, those children most at risk are the most vulnerable and least likely to access basic medical care.

But as we have shown in India, where the scale and breadth of the challenge to reach these children was unprecedented, through the effective use of aid and partnership, which brings together agencies like UNICEF, supportive governments and civil society, it can be done. It also serves as a timely reminder about the real difference aid investment from the UK can make to children's lives in countries around the world, including India.

We have a window of opportunity to capitalise on India's achievement and make a real push to protect every child against polio. I want to know that, wherever I travel on this planet of ours, I will never again find a child whose life has been damaged forever by polio. We can all play a part in ensuring this happens and for that we should be proud.