Add this line in ur code
GridView1.Columns.Clear();
Replace ur code
DataTable GetBatchDetail = new DataTable();
GetBatchDetail = objAdmin.abc(FromDate, Todate, cityid, Type);
GridView1.Columns.Clear();
foreach (DataColumn col in GetBatchDetail.Columns)
{
BoundField bField = new BoundField();
bField.DataField = col.ColumnName;
bField.HeaderText = col.ColumnName;
GridView1.Columns.Add(bField);
}
GridView1.DataSource = GetBatchDetail;
GridView1.DataBind();