What did russia do to west Berlin in 1948?

In 1948, the Soviet Union imposed the Berlin Blockade, cutting off all rail, road, and water access to West Berlin, which was located deep inside the Soviet occupation zone of Germany. The Allies responded with the Berlin Airlift, a massive airlift that supplied the two million residents of West Berlin with food and other necessities for almost a year. The Berlin Airlift was a success and forced the Soviets to lift the blockade in May 1949.