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

Here is Why You Need An Adapter

The outlet and plug type used in Brazil are C and N 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

Brazil

In Brazil, outlets of type C and N are in use.

Type C

Type N