ARTICLE 11
The Commonwealth may prescribe by law fundamental principles concerning the validity and mode of collection of State taxes, in order to prevent:
1. Injury to the revenues or to the trade relations of the Commonwealth;
2. Double taxation;
3. The imposition of excessive burdens, or burdens in restraint of trade on the use of the means and agencies of public communication;
4. Tax discriminations against the products of other States in favour of domestic products in interstate and local commerce; or
5. Export bounties;
or in order to protect important social interests.