Karika 54

ūrdhvaṁ sattvaviśālastamōviśālaśca mūlataḥ sargaḥ। madhyē rajōviśālō brahmādistambaparyantaḥ ॥54॥

The Satva quality is dominant at higher regions, the tamas at neither region, and the rajas quality is dominant in the middle. Such is the state across the vast expanse of the universe.