Due to those Navagraha doshas, individuals face different obstructions & hindrances inside their existence. So as to limit and negate the malefic doshas or malefic affect of those planets, we conduct various Pujas & Yagnas. One more etymology implies that valga signifies "to paralyze" and symbolizes the power of stambhana, https://www.youtube.com/shorts/5VeSyP9JRw0