Does this reset itself after a certain amount of time or is it one and done? I'd be worried about the feature being removed when the iPad or airpods decide they've been in India for too long.
Nope, its a one time thing. When the feature is enabled, a flag is set on the iCloud account, so you can travel anywhere and have it work. At the same time, a EQ profile is pushed to the transparency mode of the Airpods, enabling the hearing aid features.
Once done, it sticks with the Airpods, unless you reset them.
However, an interesting quirk is that if you enable this on someone's airpods, and _their_ device/account does not have it 'available', they wont be able to tweak the settings on their device.