India has "never been closer" to wiping out polio, India's health minister has declared as he marked World Polio Day.

There have been no new cases for more than nine months, making it the longest polio-free period since the global eradication campaign was launched.

The only case reported this year was in the state of West Bengal in January. There were 39 cases reported over a similar period in 2010.

India is one of only four countries in the world where polio is still endemic.

The virus is also prevalent in Afghanistan, Pakistan and Nigeria.

"We are close to our goal but are not taking any chances," Health Minister Ghulam Nabi Azad said on Monday.

"Efforts will be further intensified in the country to stop any residual polio virus circulation and also to prevent any polio cases following an international importation," he said.

Officials now say that any new case of polio would be dealt with as a public health emergency.

For decades health officials and non-governmental organisations have administered large-scale immunisation programmes as India battled the debilitating disease.

But the health ministry reported that no cases were reported from the northern state of Uttar Pradesh for 18 months and no cases have been reported from Bihar over the last 13 months.

Analysts say that these are encouraging signs.

Uttar Pradesh has been one of the worst-affected regions in the world's fight against polio with hundreds of cases reported until a few years ago.

Of the 549 polio cases in India in 2008, 297 were in Uttar Pradesh.

India's efforts to reduce polio cases have been praised by international health organisations.

Every year, India holds two national immunisation days in January and February and on each of these days, nearly 170.2 million children are given polio drops.

A highly infectious disease, polio tends to strike children aged under five. It invades the nervous system, leading to irreversible paralysis.

There is no cure, but a vaccine of mouth droplets can give good protection.