Editing Geography of Nepal (section)

=== {{anchor|The Terai Region|Terai}} Terai ===
{{Main|Terai|Inner Terai Valleys of Nepal}}
Terai is a low land region containing some hill ranges. Looking out for its coverage, it covers 17% of the total area of Nepal. The Terai (also spelt Tarai) region begins at the Indian border and includes the southernmost part of the flat, intensively farmed [[Gangetic Plain]] called the ''Outer Terai''. By the 19th century, timber and other resources were being exported to India. Industrialization based on agricultural products such as [[jute]] began in the 1930s and infrastructure such as roadways, railways and electricity were extended across the border before it reached Nepal's Pahad region.

The Outer Terai is culturally more similar to adjacent parts of India's [[Bihari people|Bihar]] and [[Culture of Uttar Pradesh|Uttar Pradesh]] than to the Pahad of Nepal. [[Nepali language|Nepali]] is taught in schools and often spoken in government offices, however, the local population mostly uses [[Maithil|Maithali]], [[Bhojpuri language|Bhojpuri]] and [[Tharu languages|Tharu]] languages.

The Outer Terai ends at the base of the first range of foothills called the ''[[Sivalik Hills|Chure Hills]]'' or ''Churia''. This range has a densely forested skirt of coarse alluvium called the ''[[Bhabar]]''. Below the Bhabhar, finer, less permeable sediments force groundwater to the surface in a zone of springs and marshes. In [[Persian language|Persian]], ''terai'' refers to wet or marshy ground. Before the use of [[DDT#Use against malaria|DDT]] this was dangerously [[malaria]]l. Nepal's rulers used this for a defensive frontier called the ''char kose jhadi'' (four ''kos'' forest, one kos equaling about three kilometers or two miles).

Above the [[Bhabar]] belt, the [[Sivalik Hills|Chure Hills]] rise to about {{convert|700|m|ft|0}} with peaks as high as {{convert|1000|m|ft|0}}, steeper on their southern flanks because of faults are known as the Main Frontal Thrust. This range is composed of poorly consolidated, coarse sediments that do not retain water or support soil development so there is virtually no agricultural potential and sparse population.

In several places beyond the Chure, there are [[Doon Valley|dūn valleys]] called [[Inner Terai Valleys of Nepal|'''Inner Terai''']]. These valleys have productive soil but were dangerously malarial except to [[Adivasi|indigenous]] [[Tharu people]] who had [[Thalassemia|genetic resistance]]. In the mid-1950s [[DDT]] came into use to [[DDT#Use against malaria|suppress mosquitos]] and the way was open to settlement from the land-poor hills, to the detriment of the Tharu.

The Terai ends and the Pahad begin at a higher range of foothills called the [[Lower Himalayan Range]].