Meaning of closing off

1. The construction workers were closing off the area to pedestrians for safety reasons.
2. The company was closing off certain sections of the building for renovations.
3. The police were closing off the street to investigate a crime scene.
4. The government was closing off access to certain websites for security reasons.
5. The teacher was closing off the discussion to focus on the main point.
6. The restaurant was closing off the patio for the winter season.
7. The team was closing off the opposing players to prevent them from scoring.
8. The city was closing off the park for maintenance.
9. The company was closing off certain departments to cut costs.
10. The organization was closing off membership to new applicants until further notice.