Wote wawili mnachamganya mambo, informal sector is not a private sector. A person in private sector is regulated by one or more gov. organization. Any one engaging themselves on an informal activities e.g unlicenced business like kuuza maandazi that person (A) doesn't pay tax, (B) no one knows if mandazi are safe for human consumption because that person was not officially licensed by appropriate health organization
Kama mtu amemaliza university akaamua kufungua hardware store at near Kawamgware, but he obtain all necessary documentations, that person sio informal sector, is part of private sector. But if you finish university and you decided to go and fix cars (unlicensed), and you managed to make ends meet but your not paying taxed, Mr. Rotich will not be able to know how much money you make in a month or the work you curry is safe to you or anyone around you, and on top all that no one will protect you in case of any eventually. Huyo mtu ni part of informal sector na ana vunja sheria zote za nchi.