<prompt> Translate the following text to SwahiliIn contrast, some older power plants, built before certain Federal performance standards were put into place, are still operating without modern pollution control equipment for some emissions.  <response>: Kwa kulinganisha, baadhi ya mitambo ya zamani ya umeme, iliyojengwa kabla ya viwango fulani vya utendaji wa Shirikisho viliwekwa mahali, bado zinafanya kazi bila vifaa vya kisasa vya kudhibiti uchafuzi kwa baadhi ya uzalishaji. 