What factors could affect the amount of sunlight reaching
theearth's surface and decrease the solar constant?

The amount of sunlight and hence solar radiation reaching the Earth differs in degree due to the factors such as the changing position of the sun and the changing atmospheric conditions that regularly occurs daily. The major atmospheric determinant of the solar radiation and thus the solar constant that reaches the Earth are Clouds.

Explanation:

can u provide the graph and if its not possible

then i can tell u the segment where the

average time interval starts degrading is the segment where the car is slowing down