Remove Unused hreflang Tags | WPML

functions.php

<?php
function remove_unneeded_hreflang( $hreflang_items ){
	global $post;
	global $sitepress;

	$t_post_id = $sitepress->get_element_trid( $post->ID, 'post_page' );
	$translations = $sitepress->get_element_translations($t_post_id, 'post_page', false, true);

	if(count($translations)==1){
        unset($hreflang_items['es']);
		return $hreflang_items;
    }

	return $hreflang_items;
}
add_filter( 'wpml_hreflangs', 'remove_unneeded_hreflang' );