そのため、派遣労働者は劣悪な労働条件の下で働いている。

、。

As a result, temporary workers are working under poor labor conditions.

Literal

For-that-reason, dispatch-workers [topic-は] inferior labor-conditions [possessive-の] under [at-で] are-working.

そのため (for that reason/as a result) links this to a preceding cause. 派遣労働者 (dispatched/temporary workers) and 劣悪な労働条件 (poor labor conditions) are formal sociological compounds. ~の下で (under) marks the conditions. ~ている marks the ongoing state.