RoHS is a European Union directive that restricts the use of six hazardous substances in electrical and electronic equipment. These substances include lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls (PBB), and polybrominated diphenyl ethers (PBDE). As electronic waste becomes a significant environmental concern, RoHS ensures that products are manufactured with fewer hazardous materials, thereby reducing their environmental impact.