push notification for the registerd participants for an event
If you want to send notifications to event participants, the best way to do that is with CiviCRM Scheduled Reminders (https://book.civicrm.org/user/email/scheduled-reminders/)
or with the extension CiviRules (https://civicrm.org/extensions/civirules).

Did you look at those?

If you, after looking at them, prefer a drupal module, you can get the CiviCRM information via the CiviCRM API or maybe even via drupal views.