<general>
            <locale>
                <code>en_US</code>
                <timezone>Asia/Calcutta</timezone>
            </locale>
 </general>

if (is_readable($localConfigFile)) {
                $localConfig = simplexml_load_file($localConfigFile);
                date_default_timezone_set('Asia/Calcutta');
                if (($date = $localConfig->global->install->date) && strtotime($date)) {
                    self::$_isInstalled = true;
                }
  }