In which year did the Berlin Blockade begin by the Soviet Union?

1948

1948-49: Berlin blockade by the Soviet Union and the airlift of supplies to the citizens of West Berlin by the US and its allies

The Berlin Blockade was a significant event that occurred during the early years of the Cold War. It took place from June 1948 (started) to May 1949.
The purpose of the blockade was to isolate West Berlin and force the Western Allies to abandon the city, thereby giving the Soviet Union control over the entire German capital.
In response to the blockade, the Western Allies launched the Berlin Airlift, a massive humanitarian and logistical operation. Over the course of 11 months, cargo planes transported food, fuel, and other essential supplies to West Berlin, bypassing the blockade and ensuring the survival of the city's inhabitants. It ultimately proved successful, as the Soviet Union lifted the blockade in May 1949, realizing that their efforts to starve West Berlin into submission had failed.