USSR anti-religious campaign (1970s–1987)
A new and more aggressive phase of anti-religious persecution in the Soviet Union began in the mid-1970s after a more tolerant period following Nikita Khrushchev's downfall in 1964. Yuri Andropov headed the campaign in the 1970s when it began.
Source: Wikipedia — USSR anti-religious campaign (1970s–1987) (CC BY-SA 4.0)