Zerodha email alert to update mobile number

Got the below email from zerodha today,

"Your mobile number ********** is in the permanent blocklist by TRAI, the telecom regulator. Please update your mobile number here on Console to a new number where we may reach you when required.

If your number is operational and you are receiving all communication, you may ignore this email.

Regards,
Team Zerodha"

The number is very well functional, in fact its the primary number that has been constantly recharged since 15 years or so (in multiple operators). So, would be ignoring this email. But whats this permanent blocklist of TRAI, and did any other dimer also get this email, kindly update , thanks :-)