Louisiana is proposing a pollution credit-trading program ("emissions trading") aimed at incentivizing companies and businesses into reducing their output of pollution, such as fertilizer runoff.

In this approach, the state allocates or sells a limited number of permits to discharge specific quantities of certain pollutants over a certain time. Polluters are required to hold permits in amount equal to their emissions. Those companies that go over that threshold must buy permits from others willing to sell them.

North Carolina, Pennsylvania and Ohio have already implemented similar programs, with Minnesota and Maryland developing them as well.

In theory, the program is meant to prompt polluters who can reduce emissions most cheaply to do so, while forcing those who pollute more to pay up. Critics of the program believe it's simply gives larger, wealthier corporations the right to pollute for a price.