Complex sentence: Glazar's father, Hugo, died of pneumonia in the Soviet Union, to which he had escaped from the Nisko reservation in the General Government of occupied Poland; some 1,100 Czech Jews had been deported there by the Nazis in 1939.
Split into simpler sentences: Glazar's father, Hugo, died of pneumonia in the Soviet Union, to where he had escaped from Nisko reservation in the General Government of occupied Poland. Some 1,100 Czech Jews had been deported there by the Nazis in 1939.