You Do Need power plug adapter while traveling from India to Grenada.

Here is Why You Need An Adapter

The outlet and plug type used in Grenada is G and in India are C, D and M. This is how they look like.

India

In India, outlets of type C, D and M are in use.

Type C

Type D

Type M

Grenada

In Grenada, outlets of type G are in use.

Type G