Sattvic quality of mind and the three Gunas for pranayama Practice
Pranayamam tatah kuryannityam sattvikaya dhiya /
Yatha sushumnanadistha malah suddhim prayanti cha//(Chapter -2, Verse 6).
Therefore pranayama should, be practice daily with a sattvic quality of mind so that the impurities are removed out of sushumna nadi and cleanliness occurs. (Chapter -2, Verse 6).