For me crypto adoption is when shops have started using/accepting crypto payments.
But that is clearly not happening and so we must know whether they are just taking the increasing count of crypto users as crypto adoption or are they considering any other factors.
I do not think it would be right to consider that adoption only means whether shopkeepers in India accept cryptocurrencies as a payment method. If that were the situation then Europe would be topping the list. It would be best if you read the Chainanlysis report rather than reading the Cointelegraph article. I did read it and I am quoting below the 5 parameters they considered before concluding that India is leading in crypto adoption.
[2] Retail centralized service value received ranking.
[3] P2P exchange trade volume ranking.
[4] DeFi value received ranking.
[5] Retail DeFi value received ranking
Source.