buttons: [{
                extend: 'excel',
                header: true

            }, {
                extend: 'print',
                header: true
            }
            ],

<table id="example" style="color: black;" class="display compact cell-border" cellspacing="0">
                            <thead>

                                <tr>
                                    <th rowspan="2">Sl.No</th>
                                    <th rowspan="2">Zone</th>
                                    <th colspan="2">Allotted</th>
                                    <th colspan="2">Vacant</th>
                                    <th colspan="2">Amenities</th>
                                    <th colspan="2">Total</th>
                                </tr>

                                <tr>
                                    <th>No Of Plots</th>
                                    <th>Area</th>
                                    <th>No Of Plots</th>
                                    <th>Area</th>
                                    <th>No Of Plots</th>
                                     <th>Area</th>
                                    <th>No Of Plots</th>
                                    <th>Area</th>

                                </tr>
                            </thead>
                        </table>