What conditions enable $RuBisCO$ to function as an oxygenase? Explain the ensuing process.

(N/A) $RuBisCO$ is an enzyme that acts as both a carboxylase and an oxygenase.
Its function depends primarily on the relative concentrations of $CO_2$ and $O_2$.
When $O_2$ concentration is high and $CO_2$ concentration is low,$RuBisCO$ binds with $O_2$ instead of $CO_2$.
This process is known as photorespiration.
In this pathway,$RuBP$ combines with $O_2$ to form one molecule of $3$-phosphoglycerate and one molecule of phosphoglycolate.
This process is considered wasteful because it does not produce $ATP$ or $NADPH$ and results in the loss of previously fixed carbon as $CO_2$.