diff --git a/includes/sanitizers/class-amp-style-sanitizer.php b/includes/sanitizers/class-amp-style-sanitizer.php
index a078e12264d..53777bf68fb 100644
--- a/includes/sanitizers/class-amp-style-sanitizer.php
+++ b/includes/sanitizers/class-amp-style-sanitizer.php
@@ -2898,17 +2898,11 @@ private function finalize_stylesheet_group( $group, $group_config ) {
 		$max_bytes      = $group_config['cdata_spec']['max_bytes'] - strlen( $group_config['source_map_comment'] );
 
 		$previously_seen_stylesheet_index = [];
-		$indices_by_stylesheet_element_id = [];
 		foreach ( $this->pending_stylesheets as $pending_stylesheet_index => &$pending_stylesheet ) {
 			if ( $group !== $pending_stylesheet['group'] ) {
 				continue;
 			}
 
-			// Keep track of the element IDs for the stylesheets.
-			if ( $pending_stylesheet['node'] instanceof DOMElement && $pending_stylesheet['node']->hasAttribute( 'id' ) ) {
-				$indices_by_stylesheet_element_id[ $pending_stylesheet['node']->getAttribute( 'id' ) ] = $pending_stylesheet_index;
-			}
-
 			$stylesheet_parts = [];
 			$original_size    = 0;
 			foreach ( $pending_stylesheet['stylesheet'] as $stylesheet_part ) {