The namespace quota for a tenant is the number of namespaces HCP reserves for the tenant out of the total number of namespaces the system can have. At any given time, the tenant can own only as many namespaces as specified by this quota.
The namespace quota is set when the tenant is created. HCP system-level administrators can change this quota at any time. However, the quota cannot be set lower than the number of namespaces the tenant currently owns.