I don't know if every nation is doing it, however it appears to look to be at least be a G20 operation. How much airspace of geographic area do you need access

I don't know if every nation is doing it, however it appears to look to be at least be a G20 operation. How much airspace of geographic area do you need access to in order to cloud seeds in other parts of the world though? I haven't looked but perhaps GeoengineeringWatch.org has resources and has kept track of that?