Complex sentence: The movie is set in the period of the emergency in India, i.e., the 21-month long period from 1975 to 1977 when Prime Minister Indira Gandhi had unilaterally declared a state of emergency across the country.
Split into simpler sentences: The movie is set in the period of the emergency in India. It is based on the 21-month long period from 1975 to 1977, when Prime Minister Indira Gandhi had unilaterally declared a state of emergency across the country.