Please block e-mail responses of a user

The user A S Narang https://launchpad.net/~asnarang-j seems to have lost control over his e-mail and it is misused for spamming.

This is now the second time within a week, that there were dubious nonsense e-mails coming from his address, adding comments to all his subscribed questions and bug documents (and in turn leading to mail notifications to all other persons who subscribed to these documents).