Airtel's big email blunder

Today I received an unsolicited email from Airtel touting its Indian Independence Day based Jayahe commercial promotion. Normally I delete such mails without a second thought, but was stunned to see that Airtel's mass mail to its customers had sent such an email with email addresses visible in the to field.

Take a look (I've obscured/erased the email ids for privacy) at the screen shot of my email. Over 500 email ids were visible to potential scammers and spammers.
I hope this fiasco is limited to Airtel's AP circle and hopefully is more minimised. If any of you know higher ups in Airtel I hope you'll escalate this potentially disastrous issue to them.