They would drop supplies from planes that flew over West Berlin.
There are no states that are prohibited from taxing by the U. S. Constitution. Such a prohibition may or may not be placed in the State's Constitution or Charter or such.
Hope this helps.
Britain didn't become a part of the Roman Empire when Gaul did because the channel of water between Britain and Gaul was an obstacle.
The Romans didn't find it easy to cross these huge amounts of water, which is why their conquering of Britain came later than nearby Gaul. Gaul was pretty much today's France - today we the means to travel between these two countries easily, but that wasn't the case back in the day.
Probably because any activities related to environment protection require a change of mentality and habits and participation of everyone in order to be fruitful.