What is the practice of protectionism?

Protectionism is an economic policy of protecting domestic industries against foreign competition by means of tariffs, subsidies, import quotas, or other restrictions or handicaps placed on the imports of foreign competitors.

Protectionism is helpful for developing economies until they can stand toe-to-toe with developed economies. It also helps in making defense industries self-sufficient.

For further reading check the following articles:

• Portuguese India
• British Raj
• Dutch Colonialism in India