*Lit petroleum, breaking law (11)
I believe the answer is:
legislation
'law' is the definition.
(I know that law can be written as Legislation)
'lit petroleum breaking' is the wordplay.
I cannot quite understand how this works, but
'lit' could be 'on' (eg a light that is switched on) and 'on' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for legislation that I've seen before include "Group of laws" , "Laws collectively" , "Passing of bills" , "Lawmaking" , "Enacting of laws" .)