If you wanna fly your UAV in Bhutan, then you have to sign a form from the BCAA, so email them to ask for it.
On the form you fill in your personal information, en you have to sign it, and promise that you will respect there UAV rule / law.
Maximum take-off weight: Max. 6 kilo
Maximum hight: 90 meters / 295 ft from ground/water level.
Maximum horizontal distance: UAV pilot must keep visual contact with the UAV
Minimum age: Not known
Insurance: Not known
Distance Airports / Heliports: 5 km / 3,18 mi.
Night flights: Prohibited
Prohibited: Not above graveyards, rescue workers, buildings, cars, boats, tempels.
Useful link: Bhutan Civil Aviation Authority (BCAA)
Contact information: firstname.lastname@example.org / +975 08271347