<?php
use Carbon\Carbon;

$file = fopen("/home/ayush/file.csv", "r");

$rows = [];

while (($data = fgetcsv($file)) !== false) {
  $rows[] = $data;
}

fclose($file);

$header = array_shift($rows);

usort($rows, function ($a, $b) {
  $dt1 = Carbon::createFromFormat("d/m/Y H:i:s", $a[15])->settings([
    "timezone" => "Asia/Kolkata"
  ]);
  $dt2 = Carbon::createFromFormat("d/m/Y H:i:s", $b[15])->settings([
    "timezone" => "Asia/Kolkata"
  ]);

  return $dt1->greaterThanOrEqualTo($dt2);
});

$file = fopen("/home/ayush/file_sorted.csv", "w");

fputcsv($file, $header);

foreach ($rows as $r) {
  fputcsv($file, $r);
}

fclose($file);