There are no specific rules for creating a local board. I think this reply best explains it.
The brief answer is that posting translated coin announcements in Other languages/locations threads is -snip- Best advice I can give you right now is to help create an active Pakistani community on Bitcointalk, it's a long term effort and in the end the forum might help you expand in a board of your own. However, the latest local board created was the Philippines one, before it being created their lthread had ~600 pages.
So that statement was given by Cyrus in 2016, almost 6 years ago and the Pakistan board is very active now as compared to 2016 era. As it says, we should have 600 pages at least, so now we have 592 pages, lets see if we hear any good news once we reach the 600 Mark
Just to be more clear, the Philippines board was created after their thread got 600 pages, how about Nigeria? Did their local thread also got 600+ pages ?