Complex sentence: Many Jewish communities, especially those which identify with religious Zionism, recite Hallel on Yom Ha'atzmaut (Israeli Independence Day) and some also recite it on Yom Yerushalayim (the day commemorating the reunification of Jerusalem in 1967).
Split into simpler sentences: Many Jewish communities, especially those that identify with religious Zionism, recite Hallel on Yom Ha'atzmaut (Israeli Independence Day). Some also recite it on Yom Yerushalayim (commemorating the re-unification of Jerusalem in 1967).