Eliminating polio is a feather in India's cap, Dr Thomas Frieden said.
While India has been polio-free since last year, it should be on the guard against importing the wild poliovirus from neighbouring Pakistan, says Dr Thomas Frieden, head of the US Centers for Disease Control and Prevention.
Dr Frieden, often described as the most high profile disease detective for the world, as head of the CDC in America, spearheads the response on all global infections like Ebola, swine flu, tuberculosis or Malaria.
Speaking exclusively to NDTV, he said that with its vast population of 1.2 billion people, India has many health challenges including controlling tobacco use, providing cheap and effective vaccines to the large numbers.
The country should also be on the watch against the 'very real' threat of 'non-state actors' getting their hands on bio-weapons, he said.
Listing the current health challenges, Dr Frieden said, "It would be fantastic if someone comes up with a vaccine against TB. It will win a Nobel Prize."
"Tobacco is also a big problem for India. It should be taxed higher and packs should carry bigger warnings," he said.
"I don't think any country in the world is doing enough on tobacco control. India still has a significant problem with beedis that are not regulated, not taxed and sold in small numbers making poor people very sick," he said.
But the doctor, who spent more than five years working on India's tuberculosis program that helped save an estimated three million lives, also lists some successes.
"India has done well to contain the spread of HIV and AIDS. But the guard should not be lowered as HIV AIDS can strike back," Dr Frieden said, adding the eliminating polio was a commendable effort.