The formation of International Mountain Day dates back to 1992 when Agenda 21 "Managing Fragile Ecosystems: Sustainable Mountain Development" was adopted at the United Nations Conference on Environment and Development.
Seeing the increasing attention towards the importance of mountains, the UN General Assembly declared in 2002 the UN International Year of Mountains and designated 11 December as International Mountain Day from 2003.
The first time International Mountain Day was celebrated was on 11 December 2003.
Every year it is celebrated with a particular theme.
The theme of International Mountain Day 2021 is "Sustainable mountain tourism."
What are mountains?
Mountain refers to landformthat rises prominently above its surroundings, generally exhibiting steep slopes, a relatively confined summit area, and considerable local relief.
Mountains generally are understood to be larger than hills, but the term has no standardized geological meaning.
Types of mountains
Volcanic Mountains: Volcanic mountains are formed when a tectonic plate is pushed beneath another (or above a mid-ocean ridge or hotspot) where magma is forced to the surface.
Fold Mountains: They occur when two tectonic plates collide at a convergent plate boundary, causing the crust to over-thicken.
Block Mountains: Such mountains are caused by faults in the crust, a seam where rocks can move past each other.
Also known as rifting, this process occurs when rocks on one side of a fault rise relative to the other.
The uplifted blocks become block mountains (also known as horsts) while the intervening dropped blocks are known as graben (i.e. depressed regions).
Important mountain ranges in India
Himalayas: The world's highest mountain range, the Himalayas, spans five countries including India.
Aravalli Range: The oldest mountain range of India, the Aravalli Range is also the oldest mountain range in the world.
Satpura and Vindhaya Range: The Satpura and Vindhaya Range lies in central India and both these ranges run parallel to each other. Both Satpura and Vindhaya are mainly situated in Madhya Pradesh and Maharashtra with some extension to Gujarat, Chattisgarh and Uttar Pradesh.
Western Ghats: Western Ghats is 1600m long mountain range that runs from Gujrat to Kanyakumari in south India.
This mountain range is also called "Sahyadri Mountains".
It comprises the mountain range of Nilgiris, Anaimalai and Cardomom.
Eastern Ghats: Eastern Ghats is mountain range running in eastern part of Indian Peninsula parallel to Bay of Bengal. This range is not continuous and is lower in elevation when compared to Western Ghats.