How can I reduce the number of emails sent by JIRA, without setting it to zero?

[almie.vanasten@cerescon.com]

With every status change an email is sent, causing to much email traffic for the users. How can I reduce the number of emails? For example only sent an email at a status change from open to investigate.

[Sreenivasaraju P]

You can add custom mail event and configure these events to the transition (on which you want the notification ) . 

 https://confluence.atlassian.com/jirakb/configure-a-custom-event-notification-for-a-specific-jira-workflow-transition-or-status-720831525.html 

You create your custom notification schema and recipients  to events to which you want to receive mails.

https://confluence.atlassian.com/adminjiraserver/creating-a-notification-scheme-938847330.html