$sort = array(
            'ACTIVE_FROM' => 'DESC',
            'SORT' => 'ASC'
        );

        $filter = array(
            '=ACTIVE' => 'Y',
            '=IBLOCK_ID' => 21,
        );

        $select = array(
            'ID',
            'NAME',
            'DETAIL_PAGE_URL'
        );

        $iterator = CIBlockElement::GetList($sort, $filter, false, false, $select);

        $result['ITEMS'] = array();
        while($ob = $iterator->GetNextElement())
        {
            $item = $ob->GetFields();
            $item['PROPERTIES'] = $ob->GetProperties();

            $result['ITEMS'][] = $item;
        }