I tried to dig a little into how these numbers are being calculated. Most are based on surveys of Indian Internet users, which caters to selection bias of "internet users in India who want to earn money using surveys". Additionally, India has a 47% internet penetration, which most reports (citing the surveys) don't seem to be accounting for.
The-Ken[c] did a report about how the number of Crypto users in India seems to be over-reported, on two counts - Users have accounts at multiple exchanges (Double Counting) and Users who are in it for the Free Crypto:
> Estimates peak at an overly enthusiastic 100 million crypto owners, as claimed by broker discovery and comparison platform BrokerChooser, but the true number is likely a more conservative 10 to 15 million, according to three industry executives The Ken spoke with.
> “We work with an internal estimate of about 4 to 5 million regular users in India,” said an executive at crypto exchange ZebPay. [...] Notably, the exchange takes into account not just individuals who made trades in the last 30 days, but also app opens while calculating the number of regular users.
> The situation is further exacerbated by exchanges offering joining bonuses and crypto rewards for signing up, like the Rs 100 worth of free bitcoin offered by crypto exchange CoinDCX.
> This lures users into creating an account—irrespective of whether they engage with it in the future or not—and helps the exchange pad up its user numbers.
A better source to consider is the Reserve Bank of India, which has made 2 interesting statements about the number of crypto investors in India.
1. RBI Governor Shaktikanta Das, Nov 2021: "With a reasonable amount of confidence, I can say the number of investors in the crypto market seems to be exaggerated. Adding that most of the buyers of cryptos in those platforms have anyway invested just between Rs 1,000 and Rs 3,000. (12-36USD). [a]
2. RBI Deputy Governor T Rabi Sankar, Feb 2022: "there is no data to justify how many investors have invested in these instruments and what is the amount of investment. Data informally gathered in November seems to indicate that crypto investments by Indians is nowhere near to being significant (although the pace of growth could make it a concern in future). This data showed that four out of five investor accounts held investments of less than ₹10,000 (122USD), with an average holding size of ₹1,566 (20USD). Wealth loss, if at all it is a possibility, is likely to affect only a small fraction of these investors." [b]
I also tried to dig into the original number from Triple-A (Which seems to have gotten a lot of traction because it was quoted in a policy-brief from UN-CTAD[5])
Here's where the number is coming from:
1. Triple-A, Crypto Firm, 2023 Figure[1] is 97.5M / 7.1% of India. The citation for this is their 2022 Report[4] (now deleted).
2. Finder.com, Stats Firm, latest figure is 29% based on a survey of 31k Indians[2]. 29% figure is based on self-selected participants, which are "internet, smartphone and Google AdMob users or Qualtrics research panel participants.".
3. Triple-A, Crypto Firm, 2022 Report[4], claims "over 100 million people, 7.30% of India" and cites HootSuite's Digital 2020 report along with Statista.
4. HootSuite numbers (survey backed), % of Internet Users aged 16 to 64 who own any form of cryptocurrency:
4.1 Digital 2023 - 16.8% [6]. Cites GWI-Q3-2022
4.2 Digital 2022 - 12.6% [7]. Cites GWI-Q3-2021
4.3 Digital 2023 - 7.1% [8] - *this seems to be the figure being used by Triple-A*, which ought to have an upper bound of 2.1% or so (63% of India is aged 15-64, with a 47% internet penetration). Cites GWI=Q3-2019.
HootSuite in turn cites GlobalWebIndex, which is again survey backed, and I couldn't find any clarity about the methodology.
5. Statista, Stats Firm, Paywalled[9]. This is again survey backed: "Which of these financial products and investments do you currently use/own? (multi-pick)". The figures shown here concern respondents who selected the option "Cryptocurrency (e.g. Bitcoin)". I found a citation for their 2020 Figure[10], which puts an upper bound on this at 12% or so.
[a]: https://bfsi.economictimes.indiatimes.com/news/fintech/numbe...
[b]: https://m.rbi.org.in/scripts/BS_ViewBulletin.aspx?Id=20870. Highly recommend reading this, as it tackles exactly the argument here ("so many Indians have already invested in cryptocurrencies and banning cryptocurrencies would lead to a loss of wealth for them. There are three reasons such arguments do not appear justified...")
[c]: https://the-ken.com/tokenised-edition/the-double-counting-fl...
[1]: https://triple-a.io/crypto-ownership-india-2022/
[2]: https://www.finder.com/in/finder-cryptocurrency-adoption-ind...
[3]: https://bitcoinke.io/wp-content/uploads/2021/10/Geography-of...
[4]: https://archive.is/icGl5
[5]: https://unctad.org/system/files/official-document/presspb202...
[6]: https://www.slideshare.net/DataReportal/digital-2023-india-f... Slide 48
[7]: https://www.slideshare.net/gangavidya/digital2022indiafebrua... Slide 47
[8]: https://www.slideshare.net/DataReportal/digital-2020-india-j... Slide 35
[9]: https://www.statista.com/statistics/1202468/global-cryptocur...
[10]: https://www.mdpi.com/2227-7390/9/24/3263