Q: I submitted a paper and for six months it was in "Under Review." How long I have to wait for an answer?

First of all, congratulations! Your article was considered for a peer review. That is a good sign! Based on what your description of the situation, it appears as though the journal is editor is currently unavailable to consider your revision. Editor unavailability could arise due to several reasons - the editor who initially looked at your paper may no longer be with the journal, especially since it has been over 6 months, and this might be increasing your waiting period. It could also be that the journal editor is currently busy trying to manage a large inflow of new submissions and has been unable to look at existing manuscripts for a while. 

In any case, since ir has been several months since you first submitted your paper to the journal, you could consider following up with the journal to understand the status better. 

We have received similar queries from authors who would like to know the status of their manuscript with the journal. You might be interested in reading the following, too:

• My manuscript's been "Under Review" for 3 months. How long should I wait to contact the journal editor for an update?
• What should I do if my paper has been under review since 5 months and the journal is unresponsive?
• What should I do if my revised manuscript is still under review and my thesis defense is getting closer?
• The status of my manuscript is "With editor" for more than 6 months. What should I do?
• Can I inquire with the editorial office if my manuscript's status hasn't changed for 5 months?