Answer:
When Indian plate collided with Eurasian plate created Himalayan Mountains.
Step-by-step explanation:
The cause for the Himalayan Mountains to exist is due to Continental drift. This is caused by the collision of Indian and Eurasian plates typically known as continent-continent collision. Enormous amount of pressure is created in this situation to give rise to a gigantic mountain uplift.
During this process, sedimentary rocks got folded in a large scale in the Earth's crust called Tethys. The maximum elevation in this region is Mount Everest of 8848 m which is the highest point on the Earth. This mountain region along with Tibet plateau provides water to one-fifth of the world's population.