Add parent cat_name_in_title Yoast SEO
add_filter('wpseo_replacements', 'city_wpseo_replacements');
function city_wpseo_replacements( $vars ) {
global $wp_query;
$cat = get_category(get_query_var('cat'),false);
$cat_parent = $cat->parent;
$cat_name = get_the_category_by_ID( $cat_parent );
if ($cat_parent) {
$cat_name = get_the_category_by_ID( $cat_parent );
} else {
$cat_name = '';
}
$vars['%%parent_cat_title%%'] = $cat_name;
return $vars;
}