date_default_timezone_set("Asia/Kolkata");
// List of Supported Timezones https://www.php.net/manual/en/timezones.php
<?php
$date = new DateTime("now", new DateTimeZone('America/New_York') );
echo $date->format('Y-m-d H:i:s');
echo date_default_timezone_get(); //UTC
//Read more at https://www.php.net/manual/en/function.date-default-timezone-get.php