Complex sentence: They were forced to live and work in disease infested; appalling conditions and when the owners refused to show signs of improvements, the population organized workers strike which left the sugarcane factories unproductive.
Split into simpler sentences: They were forced to live and work in disease infested; appalling conditions. Starting in the late 1940s one such strike owners refused to make any improvements, the population organized workers strike which left the sugarcane factories unproductive.