Here's why:

* Convergent Boundaries: These occur when two tectonic plates collide. The type of boundary depends on the types of plates involved.

* Continental-Continental Collision: In this case, two continental plates (the Indian Plate and the Eurasian Plate) are pushing against each other. Since both plates have similar densities, neither can subduct (slide) beneath the other.

* Mountain Building: The immense pressure from the collision causes the land to buckle, fold, and uplift, forming massive mountain ranges like the Himalayas.

Let me know if you'd like more details about the process!