Bulk delete all terms of given taxonomy [Wordpress]

delete_all_terms.php

function delete_all_terms(){
	$taxonomy_name = 'city';
	$terms = get_terms( array(
		'taxonomy' => $taxonomy_name,
		'hide_empty' => false
	) );
	foreach ( $terms as $term ) {
               wp_delete_term($term->term_id, $taxonomy_name); 
	    }		 
}
add_action( 'wp_head', 'delete_all_terms' );