Use the following commands.
$git tag -d <TagName>
$git push origin :refs/tags/<TagName>
Following an example.
$git tag -d v3.0.2
$git push origin :refs/tags/v3.0.2
NOTE: It is an example of a tag created/pushed/remove in a fork project cloned locally which has a remote/upstream setup to a repository where the tag v3.0.2 was previously pushed.