Day of Mobilization against the Threat of Nuclear War is celebrated around the world on the anniversary of the adoption of Delhi Declaration, which aims to call for an end to the nuclear arms race, and the subsequent reduction of phasing out nuclear arsenals of the world and the elimination of the threat of nuclear war. Delhi Declaration was adopted on January 29, 1985, in the Indian capital New Delhi at the meeting of Heads of State and Governments of several countries – India, Greece, Mexico, Argentina, Tanzania and Sweden, which became the first countries to sign the document. Today’s holiday is rooted in the fact of adoption of the Declaration on Principles of weapon-free and non-violent world. Currently, many countries have nuclear weapons in their arsenal, but its use is prohibited. This is due to the sad events of 1945, when two bombs were dropped on the Japanese cities of Hiroshima and Nagasaki that took many lives, and the consequences of these events are still felt.