using time zone in pandas to_datetime

You can use tz_localize to set the timezone to UTC/+0000, and then tz_convert to add the timezone you want:

start = pd.to_datetime('2015-02-24')
rng = pd.date_range(start, periods=10)

df = pd.DataFrame({'Date': rng, 'a': range(10)})  

df.Date = df.Date.dt.tz_localize('UTC').dt.tz_convert('Asia/Kolkata')
print (df)
                       Date  a
0 2015-02-24 05:30:00+05:30  0
1 2015-02-25 05:30:00+05:30  1
2 2015-02-26 05:30:00+05:30  2
3 2015-02-27 05:30:00+05:30  3
4 2015-02-28 05:30:00+05:30  4
5 2015-03-01 05:30:00+05:30  5
6 2015-03-02 05:30:00+05:30  6
7 2015-03-03 05:30:00+05:30  7
8 2015-03-04 05:30:00+05:30  8
9 2015-03-05 05:30:00+05:30  9

Working with time zones.

If need add Timedelta only:

df.Date = df.Date + pd.Timedelta('05:30:00')
print (df)
                 Date  a
0 2015-02-24 05:30:00  0
1 2015-02-25 05:30:00  1
2 2015-02-26 05:30:00  2
3 2015-02-27 05:30:00  3
4 2015-02-28 05:30:00  4
5 2015-03-01 05:30:00  5
6 2015-03-02 05:30:00  6
7 2015-03-03 05:30:00  7
8 2015-03-04 05:30:00  8
9 2015-03-05 05:30:00  9

NOTE: Adding Timedelta will change the epoch timestamp associated with the datetime object. This may not be desired for many applications.