The Research Early scientists often made two mistakes about anti-matter. Some thought it had a negative mass and would thus feel gravity as a push rather than a pull. Today's theories of the universe say that there is no such thing as a negative mass. The total combined mass of both elements are released in a spectacular blast of energy.
Space seems the only place, both for storage and for large-scale production.
On Earth, gravity will sooner or later pull any anti-matter into disastrous contact with matter. However, this only works for charged particles, it does not work for anti-neutrons, for example. There may be no natural anti-matter anywhere. It seems unlikely that more matter than anti-matter should be formed. In this scenario, the matter would have to exceed the anti-matter by one part in 1000 million.