You haven't provided the complete inputs to enable the members to respond or suggest. Which countries do you have projects in? You mentioned 'etc,' which doesn't give accurate inputs for any suggestions. Also, your query isn't clear. Do you want to implement shifts in India or in the countries where your teams work on projects?
Aligning Shifts with Time Zones
A better approach could be to check the different time zones of the countries where you have projects and then align them with IST. If you need to cover countries like Jamaica and other countries in North America, where the time zone difference is greater than 9-10 hours, you may need to implement three shifts. There are many websites that provide time zone information, such as
World Time Engine - Current Local Time Right Now.
If you have any specific queries, please revert back. All the best.
Regards, TS