There's a new minority to contend with and, at a little over 33,000, they are fewer in number than the Parsis. But the unbelieving atheists -- counted separately for the first time in Census 2011 -- just cannot agree with the figure.
To be precise, only 33,304 of India's 1.2 billion citizens have declared themselves as atheists in the census -- a minuscule 0.0027 per cent.
In an overtly and fervently religious country, this low figure may not come as a surprise, but atheists are simply not buying it. They accuse the powers that be of everything from "dishonesty" to "unscientific" methodology -- all aimed at "mischievously" skewing the data.
"There are millions of people in India who don't subscribe to any caste or religion. They call themselves atheists, rationalists or non-religious people," says G. Vijayam, Executive Director of the Atheist Centre in Vijayawada.
"When you say there are only a few thousand atheists, it's a distortion of reality," Vijayam told IANS. "This is mischief done by orthodox people and the Census authorities, and it must be corrected."
As far as Prabir Ghosh of the Science and Rationalists' Association of India is concerned, the very reason for the skewed numbers are these "orthodox people" who dominate those tasked with conducting the census -- the enumerators.
And he speaks from experience. When the enumerator who visited his house failed to ask him his religion, Ghosh questioned him, "What have you written in the religion column? He replied, 'Why... Hindu. You are a Hindu, aren't you? You have a Hindu surname'."
"I protested and told him to write 'atheist' against my name. He got cut up, and said that it would involve a lot of rewriting. I took the paper from him, and crossed out the word 'Hindu' from the column," Ghosh told IANS.
"In India, the Census is not conducted scientifically or honestly," added Ghosh, who was born in a god-fearing Bengali family but took to rationalism as an adult. He is now General Secretary of his Kolkata-based association.
There are quibbles as well over the numbers at the state level. The Census data, for instance, puts the number of atheists in Tamil Nadu -- a state with a strong rationalist tradition -- at a mere 1,297, a figure that "does not reflect the actual position", according to Suba Veerapandian, General Secretary of the Dravida Iyyakka Tamizhar Peravai.
"Our organisation itself has around 2,000 members. Moreover, we have the Dravida Kazhagam, the mother organisation for all the rationalist movements in Tamil Nadu, having a large membership," said Veerapandian, who was influenced by his father Subbiah, a staunch follower of Periyar.
A good number of active atheists believe the low numbers may be a result of lack of awareness about what can and cannot be said in the Census form.
"Many Indians are not aware that they have an option to say 'no caste' or 'no religion'," says Vijayam, whose father founded the Atheist Centre that has fought many battles on behalf of those who wrote 'nil' in caste and religion columns of various government forms.
Veerapandian concurs, but adds that it is up to atheists and rationalists to power change -- the matter hardly being a priority for the government. "It should be made known to people, and organisations like ours will have to do that before the 2021 Census."
In fact, many atheists and rationalists want the government to entirely remove the caste and religion columns from not only the Census forms, but all forms.
"We are a secular state and there is no necessity to write caste and religion. When people say we don't have property, you are accepting that. Similarly, accept when they say they don't belong to any caste or religion," says Vijayam.
Are atheists playing it safe by not declaring themselves openly? It is a legitimate question as three prominent rationalists -- Narendra Dabholkar, Govind Pansare and M.M. Kalburgi -- have been killed in the last two years for challenging obscurantism, allegedly by religious hotheads.
But Ghosh and Veerapandian dismiss the idea. "Why should they try to hide their belief? Even in a Muslim area, Hindus announce their religion, and vice versa. So why should atheists be afraid," Ghosh queried.
Given that there are nearly 2.9 million people who did not tell enumerators their religion -- though they did not declare themselves as atheists -- there may well be many more atheists than the declared number.
In any case, the non-believers are upbeat. Ghosh, for instance, contends 22 per cent of the world population is now atheist, and that the number is growing. He believes the trend will be replicated in India as well.
Adds Vijayam: "Atheism has come to stay. It's a worldwide phenomenon and when opportunity comes they all will come out of religion."
(With inputs from Sirshendu Panth in Kolkata; V. Jagannathan in Chennai and Mohammad Shafeeq in Hyderabad)