Setting the correct timezone is very important in any system to avoid confusions. Especially in systems used by multiple users, one may think the time is wrong without noticing the timezone.
To verify the date and time, including the timezone set in a linux (CentOS) host, the below is a very useful command:
Tue May 17 10:26:49 EDT 2016
Now the question is how did the system pick EDT? This get configured during the time of installing the OS.
The following steps can be used to reset the timezone to IST.
#] mv localtime /root/
#] ln -s /usr/share/zoneinfo/Asia/Kolkata localtime
Now let us verify of the change happened.
Tue May 17 10:34:07 IST 2016