By the mid-20th century, Abadan became the world's largest oil refining center. The huge oil refining complex processed crude oil delivered via pipelines from the Khuzestan fields, and then sent petroleum products for export. The city grew rapidly: its population increased from a few hundred people at the beginning of the century to hundreds of thousands by the middle of the century. The city's economy was almost entirely dependent on the oil industry and the activities of the Company that managed oil refining and export.