What do you see as the main reasons for the development of glasnost during the years of perestroika?

The policy of glasnost became possible during the Perestroika period, which Mikhail Gorbachev began to carry out in the USSR, in the period from 1986. It was necessary for the people to report the shortcomings of the party and bureaucratic system of socialism. The course towards democratization and the abolition of censorship gradually led to the emergence of opposition in various republics of the USSR, which ultimately led to its collapse. Publicity was one of the factors in this event. By 1991, it had become complete, dissidents were released from prisons. The first presidential elections in the USSR were also held.