That renunciation is considered sattvic, O Arjuna, when one performs prescribed action as a duty, giving up attachment and the fruit.

Here is the sattvic tyāga — the genuine renunciation that the Gita has been pointing toward throughout. It has three characteristics: the action is niyata (prescribed by one's duty), it is performed kāryam iti — simply because it ought to be done, as a matter of dharmic necessity — and it is performed with both saṅga (attachment to the process) and phala (desire for the fruit) fully released. The simplicity of this formulation is radical: do your duty because it is your duty, neither clinging to how it goes nor grasping at what comes from it. This is the posture of the liberated actor — fully engaged in the world, fully free from the world.