Reports in local media have put the new estimate at around three to 3.5 million cases.
Officials said the massive drop could be attributed to the fact that the data available this year is better than ever.
"There are more sentinel sites than before so we have a better picture of the epidemic," said Broun, referring to testing sites where samples are taken from members of both low- and high-risk groups, to be used as markers.
"We also have a population-based survey, we have a good behavioural surveillance survey, a whole set of surveys has been done in high-presence states among high-risk groups."
More than 1,100 testing sites were used this year as compared to 700 in the past, NACO's epidemiologist Ajay Kumar Khera told AFP.
The north was under-represented before, he said, skewing nationwide estimates towards southern states with higher rates of infection.
And a wide-ranging population health survey tested 100,000 adults randomly between December 2005 and August 2006.
International health organisations have for years worried about the possibility of a South Africa-style AIDS epidemic in India, but the new figures being mentioned would mean a fairly low infection rate.
However organisations that work with high-risk groups such as commercial sex workers, intravenous drug users and homosexual men said their work will go on as before.
"We will continue doing the work we do because that's what we believe is important," said Anjali Gopalan, who heads the Naz Foundation, which works with gay men.
NACO's director said the country would not pull back on its AIDS plans even in the event of a sharply lower case count.
"It's not a curable disease. The mode of transmission is due to reasons over which there is very little human control: private and personal behaviours like sex," said Rao.
"Numbers don't matter. To bring in behaviour change is a tough call so you can't ever relax or it's just a matter of time before it can invade the whole country."
Source-AFP
LIN/M