In a move termed as trade tsunami, set to upend international trade dynamics, President Donald Trump has declared an aggressive plan to impose reciprocal tariffs on India and other nations he accuses of exploiting the United States with exorbitant duties.

Here’s what you need to know about reciprocal tariffs and who might be impacted by Trump’s plan. Reciprocal tariffs refer to tariffs—the taxes charged on imported goods—the U.S. government plans to levy against global trading partners that are equal to the existing tariffs foreign countries have set against American goods.

If the US genuinely tries to close its overall deficit with big tariffs all round, it will cause a crunching recession. If Trump discriminates between trading partners, the heavily tariffed ones can nip through the side door of those who escaped more lightly.