The Indian government has dismissed a claim by an Aids expert that the country now has the most HIV-positive people in the world.
The claim was made by Richard Feachem of the Global Fund to Fight Aids. He says figures showing India having fewer cases than South Africa are wrong.
The United Nations says that South Africa has 5.3 million people infected with the Aids virus.
The Delhi government says there are 5.1 million cases in India.
However, independent experts say the number of people infected in India could be anywhere between 2.5 million and 8.5 million - because of the lack of reliable data here in relation to the HIV pandemic.
HIV/Aids is a serious problem [in India]. We are aware of the gravity of the situation and we have programmes to deal with it
SY Qureshi, National Aids Control Organisation
India's government-controlled National Aids Control Organisation (Naco) chief SY Qureshi told the BBC that Mr Feachem's claim was "nonsense".
"Our [Aids] surveillance systems are certified by the World Health Organisation, UN agency UNAids and the Indian Council of Medical Research [ICMR].
"We stand by our figure of 5.1 million [infections]," Mr Qureshi said.