HIstorical data not correct Bank Nifty

List historical = kite.GetHistorical("12835330", startday, startday, "minute");

for (int i = 0; i < historical.Count; i++)
{
Reports.AppendHistoryCSV( Environment.NewLine + historical[i].TimeStamp.ToString() + "," + historical[i].Open.ToString() + "," + historical[i].High.ToString() + "," + historical[i].Low.ToString() + "," + historical[i].Close.ToString() + "," + historical[i].Volume.ToString());

}

2018-03-19T15:19:00+0530 24420.95 24420.95 24420.95 24420.95 24421
2018-03-19T15:20:00+0530 24420.95 24420.95 24420.95 24420.95 24421
2018-03-19T15:21:00+0530 24420.95 24450 24420.95 24450 24450
2018-03-19T15:22:00+0530 24450 24450 24450 24450 24450
2018-03-19T15:23:00+0530 24450 24450 24450 24450 24450
2018-03-19T15:24:00+0530 24450 24450 24450 24450 24450
2018-03-19T15:25:00+0530 24450 24450 24450 24450 24450
2018-03-19T15:26:00+0530 24450 24450 24450 24450 24450
2018-03-19T15:27:00+0530 24450 24450 24450 24450 24450
2018-03-19T15:28:00+0530 24450 24450 24440 24440 24440
2018-03-19T15:29:00+0530 24440 24440 24440 24440 24440

any idea?