Answer: The Himalayas are the world's highest and youngest mountain range, owe their origin to the theory of plate tectonics. This immense mountain range began to form between 40 and 50 million years ago, when two large landmasses, India and Eurasia, driven by plate movement, collided. The geological evolution of the Himalayas can be attributed to the movement and interaction of Earth's tectonic plates over millions of years.

• India’s landmass at 225 million years ago (Ma): During ancient times, India was a large landmass located off the Australian coast, separated from Asia by the vast Tethys Ocean.
• Northward-drifting at around 200 million years ago (Ma): The supercontinent Pangea began to break apart, and India initiated a northward drift towards Asia.
• Oceanic-continental convergence at around 80 million years ago: India was situated about 6,400 km south of the Asian continent and moving towards it at a rate of 9 to 16 cm per year. The Tethys Ocean floor was being subducted northward beneath Asia, leading to a convergent oceanic-continental plate boundary, much like the present-day Andes.
• Scraping of Sediments and formation of accretionary wedge: As India approached Asia, not all of the Tethys Ocean floor was completely subducted. Thick sediments on the Indian margin of the ocean were scraped off and accreted onto the Eurasian continent, forming an accretionary wedge.
• Birth of the Himalayas: These scraped-off sediments, along with the Indian continental plate, began to thrust upwards, giving rise to the Himalayas, the world's highest mountain range.
• Continental-continental convergence boundary at around 50–40 million years ago (Ma): India's northward drift slowed to about 4-6 cm per year, signifying the beginning of the collision between the Indian and Eurasian continental plates. This collision closed the Tethys Ocean and initiated the uplift of the Himalayas.
• Thickening of Continental Crust: Due to the low density and high buoyancy of both continental plates, subduction was avoided. Instead, compressional forces folded and faulted the continental crust, leading to the thickening of the crust in the region of the Himalayas and the Tibetan Plateau.
• End of Volcanic Activity: The thickening of the continental crust brought an end to volcanic activity in the region, as any magma moving upwards would solidify before reaching the surface.

The Himalayas are still rising by more than 1 cm per year as India continues to move northwards into Asia, which explains the occurrence of shallow focus earthquakes in the region today. However, the forces of weathering and erosion are lowering the Himalayas at about the same rate.