(1) The Himalayan mountain system is the world’s highest,and home to the world’s highest peaks including Mount Everest and K2. This system also includes Karakoram,Hindu Kush and other ranges extending out from the Pamir knot. The IHR physiographically,starting from the foothills of south (Siwaliks),this mountain range extends up to Tibetan plateau on the north (Trans-Himalaya). Three major geographical entities,the Himadri (greater Himalaya), Himachal (lesser Himalaya) and the Siwaliks(outer Himalaya) extending almost uninterrupted throughout its length, are separated by major geological fault lines.