The power to make laws with respect to residuary subjects (i.e., the matters which are not enumerated in any of the three lists) is vested in the Parliament.  

• This residuary power of legislation includes the power to levy residuary taxes.  
• From the above scheme, it is clear that the matters of national importance and the matters which require uniformity of legislation nationwide are included in the Union List.  
• The matters of regional and local importance and the matters which permit diversity of interest are specified in the State List.  
• The matters on which uniformity of legislation throughout the country is desirable but not essential are enumerated in the concurrent list. Thus, it permits diversity along with uniformity. 

Source: Laxmikanth