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

Here is Why You Need An Adapter

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

Namibia

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

Type D

Type M

India

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

Type C

Type D

Type M