How to export hindi data from gridview to excel file in ASP.net?

DataTable table = (DataTable)GridView1.DataSource;
            if (table != null)
                if (table.Rows.Count > 0)
                {
                    String file_name;
                    if (TextBox9.Text.Trim() == String.Empty)
                        file_name = "All_Data";
                    else
                        file_name = DropDownList1.Text + "_" + TextBox9.Text.Trim();
                    HttpContext context = HttpContext.Current;
                    context.Response.Clear();

                    Response.ContentEncoding = System.Text.Encoding.UTF8;
                    Response.ClearContent();
                    string attach = "attachment;filename=" + file_name + ".xls";
                    Response.AddHeader("content-disposition", attach);
                    Response.ContentType = "application/ms-excel";

                    if (table != null)
                    {
                        foreach (DataColumn dc in table.Columns)
                        {
                            Response.Write(dc.ColumnName + "\t");
                            //sep = ";";
                        }
                        Response.Write(System.Environment.NewLine);
                        foreach (DataRow dr in table.Rows)
                        {
                            for (int i = 0; i < table.Columns.Count; i++)
                            {
                                Response.Write(Server.HtmlDecode(dr[i].ToString() + "\t"));
                            }
                            Response.Write("\n");
                        }
                        Response.End();
                    }
                }