Complex sentence: The Central Committee elected at the 16th Party Congress (26 June--13 July 1930) removed Tomsky and Rykov, he also lost his Council of People's Commissars chairmanship, from the Politburo.
Split into simpler sentences: The Central Committee which was elected at the 16th Party Congress (26 June--13 July 1930) removed Tomsky and Rykov. Rykov also lost the Council of People's Commissars chairmanship, from the Politburo.