In this context, I presume your talking about EMI = Electro-Magnetic Interference, and not the well-known record label?

Note that reulations deal with EMC = Electro-Magnetic Compatibility - and that covers both Emissions and Susceptibility.
In other words, your equipment must neither cause interference to other stuff, nor suffer interference from other stuff.

Precisely what regulations apply depends upon both the type of equipment, and the territory in which it is to be sold/used.