Anonymous VOIP phone numbers can be obtained - in the U.S. anyway.
"The original disclosure order was issued despite fierce opposition. One of Telegram’s main defenses was that the user data is stored in Singapore, which prohibits the decryption of personal information under local privacy law. The Court dismissed this argument on the basis that the ongoing infringing activity is related to Indian works and will likely be tied to Indian users. And even if the data is stored elsewhere, it could be accessed from India. Telegram also brought up the Indian constitution, which protects people’s privacy, as well as the right to freedom of speech and expression. That defense was unsuccessful too."
Yes, none of that applies when one is suspected of committing a crime, so I don't see any "new precedent" set here.
"Telegram also brought up the Indian constitution, which protects people’s privacy."
It must do a mediocre job of that, because your prime minister seems to have no trouble circumventing it.