title: Tier 4
text: # Tier 4
  
  Tier 4 or Tier four may refer to:
  
  * Tier 4 COVID restrictions in England under The Health Protection (Coronavirus, Restrictions) (All Tiers) (England) Regulations 2020, the highest level
  * Level 4 COVID restrictions, in COVID-19 pandemic in Scotland
  * Tier-4 COVID restrictions, in COVID-19 pandemic in Wales
  * Tier IV, a data center standard
  * Tier 4 in United States vehicle emission standards
  