Code to “noindex” Single Tag Archive in WordPress

/* No Index Single Category */
add_action('wp_head', 'wpflt_header_function_condition_noindex_single_tag');
function wpflt_header_function_condition_noindex_single_tag(){
if ( is_tag( '10' ) ) { ?>
<meta name="robots" content="noindex" />
<?php }
};

Add this code to avoid indexing a specific tag in WordPress. Add the tag ID in line 4.