EMI has two major parts, the first is conducted EMI and the second is radiated EMI. Conducted EMI is generated through the parasitic impedances, power connections, and the ground connections. Radiated EMI, however, is generated through radio transmission.
EMI standards can vary by region and also by application. This means that engineers could be working on a very similar project using the same IC, but totally different standards could apply. It is important to note that the standards typically adhered to are FCC, and CISPR, which is the same as EN 55022.
EMI is getting critical as applications are getting complex with more sensors and connectivity standards. A good engineering practice is to design with EMI as low as possible at an early stage. Choosing the right EMI reduction method affects the product time-to-market, cost, and ultimately an effective EMI reduction design.