Critical Error

ErrorException: Undefined variable $indexing in /var/www/html/templates/components/meta-tags.php:30
Stack trace:
#0 /var/www/html/templates/components/meta-tags.php(30): Core\ErrorHandler::handleError(2, 'Undefined varia...', '/var/www/html/t...', 30)
#1 /var/www/html/_core/View.php(39): include('/var/www/html/t...')
#2 /var/www/html/templates/compass-layout.php(12): Core\View::part('components/meta...')
#3 /var/www/html/_core/View.php(26): require('/var/www/html/t...')
#4 /var/www/html/_core/Router.php(98): Core\View::renderPage('/var/www/html/s...', Array)
#5 /var/www/html/_core/Router.php(53): Core\Router::renderPhysical('/var/www/html/s...')
#6 /var/www/html/public/index.php(12): Core\Router::run()
#7 {main}