Return json

<?php

 require('../../../../wp-load.php');

 global $wpdb;

 $lat = $_POST['lat'];
 $lng = $_POST['lng'];
 $date = $_POST['date'];
 $hour = $_POST['hour'];

 $query = "SELECT *
FROM {$wpdb->prefix}posts
INNER JOIN {$wpdb->prefix}postmeta m1
  ON ( {$wpdb->prefix}posts.ID = m1.post_id )
INNER JOIN {$wpdb->prefix}postmeta m2
  ON ( {$wpdb->prefix}posts.ID = m2.post_id )
WHERE
{$wpdb->prefix}posts.post_type = 'agenda'
AND {$wpdb->prefix}posts.post_status = 'publish'
AND ( m1.meta_key = '_lat' AND m1.meta_value ='$lat' )
AND ( m2.meta_key = '_lng' AND m2.meta_value = '$lng' )
GROUP BY {$wpdb->prefix}posts.ID
ORDER BY {$wpdb->prefix}posts.post_date
DESC";

    $results = $wpdb->get_results($query);


    $json = array();

    foreach($results as $key => $post) {

      $id = $post->ID;
      $tit = $post->post_title;
      $ctn = $post->post_content;

      $json['local']['id'] = $id;
      $json['local']['tit'] = $tit;
      $json['local']['ctn'] = $ctn;
      $json['local']['lat'] = $lat;
      $json['local']['lng'] = $lng;
      $json['local']['hour'] = $hour;
    }


    echo json_encode($json);