Fix grammaticality of the sentence: By 1990, there were 675,000 registered estate tenants with little security, and another 580,000 “squatters” lived on surplus land with no security, forming a pool of casual labour.
By 1990, there were 675,000 registered estate tenants with little security, and another 580,000 "squatters" lived on surplus land with no security, who formed a pool of casual labour.