On March 25, the Central Epidemic Command Center (CECC) recommended that indoor events that are attended by more than 100 people and outdoor gatherings that are attended by more than 500 people be suspended, in order to prevent cluster infections. The CECC explained that organizers of these types of gatherings can conduct risk assessments based on the following six indicators described in the Guidelines for Large-Scale Public Gatherings in the Wake of the COVID-19 Outbreak: 1. ability to gain information on participants beforehand; 2. air ventilation and replacement; 3. distance between participants; 4. whether participants are in a fixed position; 5. event duration; 6. hand hygiene and surgical masks. If an assessment of the nature of the gathering finds a high degree of risk, the CECC recommends that the gathering be postponed or cancelled, or held in a different manner.