Hi Shreyansb,
Welcome to the community! The points and curves shown in pink are projected objects. They are used to build the association with other objects out of the current sketch.
When we create sketch objects, we might want to refer to existing vertices, edges, etc. and keep the association. For example, we could create a sketch line starting from the midpoint of a body edge. When the bod edge moves, we might want to have the sketch line updated to the new position.
Since the pink objects are generated based on other existing objects, they cannot be moved by dragging. We can use “Break Link” to break the association or just delete them. However, the capability of associative update will be lost.
As for the pink points shown in your screenshot, they are the end points of the projected line or the center of the arc, so they can only be deleted together with its parent object.
Here is a screencast to show how the associative update works and what will happen if deleting the projected curves.
Best Regards,

Nicolas Xu
Sr. SQA Eng.
Fusion 360 Quality Assurance Team
Autodesk, Inc.