The goal of carbon credits is to produce resources which are spent on reducing carbon in atmosphere. Reduction could happen either by polluting less, or extract

The goal of carbon credits is to produce resources which are spent on reducing carbon in atmosphere. Reduction could happen either by polluting less, or extracting carbon from atmosphere more. A cement plant can keep polluting, but will have to pay for pollutions, put that into costs and face market pressure. It can employ modern technologies, allowing to pollute less, which will make the product cheaper to sell. Or it may pay somebody to pull some carbon from atmosphere, in the form of newly planted forests. If those forests pull as much carbon from air as it gets there from forests "owners", those owners integral carbon impact is zero. Of course, it depends on many factors - how efficient the process is, how much credits were bought etc. - but those credits clearly intended to reduce the amount of carbon in the air.