1 The cantons shall enact the regulations necessary for the application of this Act.
2 Unless other authorities are designated under cantonal legislation, the cantonal governments shall be authorised to take provisional measures and in particular to determine planning zones (Art. 27) and to issue restrictive provisions on building outside the building zone (Art. 27a).86
3 Provided no building zones exist, and cantonal law does not provide otherwise, areas that are already largely built up shall be deemed to be provisional building zones.
86 Amended by No I of the FA of 23 March 2007, in force since 1 Sept 2007 (AS2007 3637; BBl 2005 7097).