$re = '/(?<=data-rlocation=").*?(?=")/m';
$str = '<p class="sm clg" data-rlocation="Uttam Nagar East">Uttam Nagar East, Delhi <span class="to-txt" id="citytt1">B-24, East Uttam Nagar, Uttam Nagar East,<br>Delhi<span> - </span>110059';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php