Concept:
A community pharmacy must follow legal requirements for medicine sale.
Step 1: Medicines should be dispensed under professional supervision.
Step 2: A registered pharmacist is legally required during working hours.
Step 3: NABH and ISO certifications are not mandatory for every community pharmacy.
Step 4: Ownership by pharmacist is not the given mandatory requirement here.
\[
\boxed{\text{Employment of a registered pharmacist during working hours}}
\]