Import substitution involves

the reduction of import tariffs so that an economy can export goods that were previously imported.
the use of import tariffs so as to encourage the local production of goods that were previously imported.
the protection of industries in which an economy would traditionally have enjoyed comparative advantage.
the substitution of local labour with imported capital so as to reduce the costs of production and ensure the competitiveness of strategic industries.

the use of import tariffs so as to encourage the local production of goods that were previously imported.