Cat ownership comes with a number of responsibilities including desexing, microchipping, and registration. You must ensure your cat does not pose a nuisance to your neighbours or be a threat to wildlife and the environment.
Keeping your cat indoors or in an enclosure is the best method to minimise nuisances to neighbours, or threats to wildlife and the environment. This also has the added benefit of keeping your cat safe and healthy.
For more information on cat ownership, you can refer to Good Cat SA.