If the writer were to delete the underlined phrase "living in caravans and camps" from the preceding sentence, the sentence would primarily lose C an indication of the living conditions that made food storage and preparation difficult.
The phrase provides important context about the transient families' living situations, which helps explain why they lacked access to refrigeration or food preservation. Without this phrase, the sentence would still convey that transient families had no access to refrigeration or food preservation, but it would lack the specific context that illustrates the challenges they faced due to their living conditions.