Zones and agglomerations layer for air quality assessment and management in the Czech Republic. The zones and agglomerations are defined on the basis of the legislative specifications of the EU Directive 2008/50/EC and Act No. 201/2012 Coll., on Air Protection. A zone is an area defined by the Ministry of the Environment for the purpose of monitoring and managing air quality; an agglomeration shall mean a zone that is a conurbation with a population in excess of 250 000 inhabitants.