Complex sentence: As communist rule was established in Vietnam after the end of the war, open practice of the Bahá'í Faith was banned from 1975 to 1992, and community numbers dropped sharply as thousands of Bahá'ís moved as refugees to the United States and other countries.
Split into simpler sentences: As communist rule was established in Vietnam after the end of the war, open practice of the Bahá'í Faith was proscribed. Community numbers dropped sharply during this time as thousands of Bahá'ís moved as refugees to the United States and other countries.