Menurut rujukan di bawah ini:

1. customs clearance = mengambil barang di pabean

2. customs clearance = dokumen pelunasan bea cukai

Nah, berdasarkan konteks pemakaian istilah tsb di teks sumber, makna 1 yg cocok.

Jadi, cargo clearance permit = izin mengambil barang/kargo.

Ref.:
Customs clearance is the act of taking goods through the customs authority to facilitate the movement of cargo into a country (import) and outside the country (export).

Also, the customs clearance means a document issued by the customs authority to a shipper indicating that all duties have been paid and the shipper’s goods is cleared for export.
https://www.saloodo.com/logistics-dictionary/customs-clearan...