How can a factory demonstrate that it has not caused soil or groundwater pollution? Is it necessary to provide relevant test reports, or is conducting internal audits sufficient as evidence?

The facility can demonstrate its internal controls and audit procedures to monitor the risk of contamination. The facility can also conduct soil investigation reports, and environment impact assessments indicating that the facility does not contaminate groundwater/soil. It's recommended that the facility should store such audit procedures, audit and investigation reports, etc in support of this. The same can be asked during the verifications.