Help with custom world time Clock JS code

Hi! I’ve got some world clocks on a site that i’m creating. And so far so good, but when it comes to Mumbai, the time difference is 4.5 hours. How can i change my custom code to include the half our difference that i need for Mumbai timer?

My JS skills aren’t very good. I understand the logic to it, but cant write the code my self.

Help is very much appreciated!

Best regards,

Here is my site Read-Only: