"levy"

means an amount payable at intervals or at specified times by participants in civil aviation, as defined in section 1 of the South African Civil Aviation Authority Act, 1998, on one or more or all of the following criteria, namely—

(a)	category of aviation service;

(b)	category of participant;

(c)	nature of aviation service;

(d)	frequency of utilisation of aviation services provided by the authorities; and

(e)	nationality of or country of registration of participant;