Here's why:

* Sheet Erosion: This is a type of erosion where a thin layer of topsoil is removed evenly across the land. In the Chambal region, this is exacerbated by factors like:

* Deforestation: Removal of trees leaves the soil exposed and vulnerable.

* Overgrazing: Excessive grazing by livestock compacts the soil, reducing its ability to absorb water and increasing runoff.

* Unsuitable Agricultural Practices: Poor farming methods like tilling the soil up and down slopes increase erosion.

* Low rainfall: While the Chambal region receives some rainfall, it's often intense and short-lived, leading to rapid runoff and erosion.

How sheet erosion creates ravines:

Over time, the continuous removal of topsoil by sheet erosion leaves deep gullies and ravines. As the land becomes more exposed and eroded, the process accelerates, leading to the formation of the extensive ravine system seen in the Chambal region.

Other factors:

While sheet erosion is the primary cause, other types of erosion like rill erosion (small channels forming on slopes) and gully erosion (larger channels) also contribute to the problem. However, sheet erosion sets the stage for these other types of erosion to occur.