OOP PHP: How to avoid ORM situation during class design?

Currently, I am working on a project of an online service provider.But I am really confused on class designing.

I have tables for actors like admin, customer, agent and tables for data storage like city, services, category, sub-category, gender.

I have created classes for the admin, customer and agent. But should I create classes for city, services, category, etc. tables which look like an ORM design as well?

Is it good to have one class for each table in a database? If not then please explain how to avoid this situation?