You Do Need power plug adapter while traveling from India to Ireland (Eire).

Here is Why You Need An Adapter

The outlet and plug type used in Ireland (Eire) 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

Ireland (Eire)

In Ireland (Eire), outlets of type G are in use.

Type G