Tehran is 2.25 hours behind Kathmandu
Best overlap: 10:15 AM to 6:15 PM in Kathmandu is 8:00 AM to 4:00 PM in Tehran.
If you set up a recurring sync, 10:15 AM to 6:15 PM in Kathmandu (8:00 AM to 4:00 PM in Tehran) is the natural home for it. Tehran is 2.25 hours behind Kathmandu, but the generous 8-hour window means both teams can meet well within their normal day.