Complex sentence: Prior to Zimbabwe's independence in 1980 he led the Commonwealth Secretariat team which monitored Zimbabwe's pre-independence elections, and through the Commonwealth Eminent Persons Group between 1982 and 1993 he was active in applying political pressure in the removal of the apartheid regime in South Africa.
Split into simpler sentences: Prior to Zimbabwe's independence in 1980 he led the Commonwealth Secretariat team which monitored Zimbabwe's pre-independence elections. Through the Commonwealth Eminent Persons Group, between 1982 and 1993 he was active in applying political pressure in the removal of the apartheid regime in South Africa.