Phil0124 wrote:
Nothing on that screen states anything about Singapore.

To Aman_221:
I do wonder whether the same mechanism is being used in India and Singapore, and the message wasn’t corrected.
Karnataka looks the closest within India to having an age ban enforced, though that’s based on a quick read of a non-authoritative source.
If your iPhone is not set to Singapore, your Apple Account is not set to Singapore, no VPNs are in use, and you’re not in Karnataka, contact Apple Support and ask them to look into this.