Export to excel in c# for multi language data coming from database

HttpContext.Current.Response.Clear();
           HttpContext.Current.Response.ClearContent();
           HttpContext.Current.Response.ClearHeaders();
           HttpContext.Current.Response.Buffer = true;
           HttpContext.Current.Response.ContentType = "application/vnd.xlsx";
           HttpContext.Current.Response.AddHeader("Content-Disposition", "attachment;filename=" + SheetName +  DateTime.Now.ToString("yyyy-MM-dd-HH-mm-ss-fff")+".xls");
           HttpContext.Current.Response.Charset = "utf-8";
           HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.GetEncoding("windows-1250");
           To = Convert.ToDateTime(To).AddDays(-1).ToString("yyyy-MM-dd");
           string html = getHTMLtableFromDataTable(dt, SheetName,From, To);

           HttpContext.Current.Response.Write(style);
           HttpContext.Current.Response.Output.Write(html);
               HttpContext.Current.Response.Flush();
               HttpContext.Current.Response.End();