org-use-tag-inheritance

org-use-tag-inheritance is a variable defined in `org.el'.
Its value is

t

Documentation:
Non-nil means tags in levels apply also for sublevels.
When nil, only the tags directly given in a specific line apply there.
This may also be a list of tags that should be inherited, or a regexp that
matches tags that should be inherited. Additional control is possible
with the variable `org-tags-exclude-from-inheritance' which gives an
explicit list of tags to be excluded from inheritance, even if the value of
`org-use-tag-inheritance' would select it for inheritance.

If this option is t, a match early-on in a tree can lead to a large
number of matches in the subtree when constructing the agenda or creating
a sparse tree. If you only want to see the first match in a tree during
a search, check out the variable `org-tags-match-list-sublevels'.

You can customize this variable.