Yes, it's both. I'd also add that sectionalism is sometimes an economic issue. What do you think?
This site may help you.
According to me ,it is mostly a political issue..because the politicians use this in order to be elected in the election to have a seat in the national assemnly.Before the leader of a political party appoints his or her candidates in certain section of a country,he or she makes sure for his or her candidates to be elected by refering or analysing the former elections..i don't know if in your society people consider caste system important for the election..but i shoul tell you that it some society..leader of political party appoints his or her candidates in certains section of the country according to the number of people who belongs to which religion or caste..
lets tke this example;
for example in the town X,the inhabitants mainly muslims who live there..the leadr is more likely to appoint a muslim candidate there..this exist in certain societies..
i only hope his information may help u..