Please don't do that. Use a hash that stores all the adresses:

package Mailer;

our( %TO );
$TO{ Chennai }= 'sriram.perumalla@ness.com';

package main;
print $TO{ Chennai };
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If you want to learn about why it's a bad practice, read http://perl.plover.com/varvarname.html and the two follow-up parts.