The populations in the high mountainous areas, such as the Himalayas in India, Andes in South America, Rocky in North America, etc., have very low settlement level. This is because the relief is rugged here which represents obstacles in the construction of roads, railways and communication. Due to steep slopes, agriculture is done with a great difficulty and industries also could not be established. These places having very less economic activity have less population and hence have small isolated settlements. Whereas the plain areas of the world are most suitable for human settlement. Fertile plains of Ganga in India, Indus in Pakistan, Hwang-Ho in China and plains of Europe have huge population concentration having compact or huge semi-compact type of settlement. 2) Climate
Most of the areas of the earth having density less than two persons/sq. km are not favorable for settlement because of their unfavorable climate. Areas of cold climate-North Siberia, North Canada, Alaska etc. have low density of population. Hot and arid regions of -Sahara, Kalahari Desert in Africa, Great Australian Desert etc are not suitable for human settlement. In tropical regions due to heavy rain and temperature, the density of population is very low, example in Amazon basin population density is less than two persons/sq. km. But places with favorable climate and favorable terrain, have dense population and hence have compact settlement. 3) Soils
Fertile alluvial soils encourage dense population which in turn gives rise to compact type of settlement. This is so because alluvial soils give rise to agricultural activities. Java Islands of Indonesia has fertile soil of young volcanic material and agriculture is an important activity, hence dense and compact settlements are found here. Whereas in Sumatra, due to infertile soil, the population density is very low. 4) Mineral Deposits
Mineral wealth is yet another factor responsible for population distribution and density. The presence of coal and iron-ore in different parts of the world has attracted huge population. Coal mining regions have become regions of dense population for example, Jharkhand in India and gold mines in Australian desert. 5) Water supply
Population distribution is very much affected by water supply. The earliest settlements or civilizations developed on the banks of major rivers, example-Nile, Indus, etc. Adequate water supply provides irrigation facilities to farmers and hence population increases due to increase in primary activities. In dry regions, population is concentrated in those areas where there is water, hence nucleated- circular settlements are found. Thus it can be said that the environment plays an important role in deciding population distribution, density, settlement type and pattern. The Industrial Revolution which provided mechanical power, invention of steam engine and other machinery, greater use of metals etc gave them opportunities to modify the environment. At the same time agriculture provided abundant food so that they could settle down permanently. The family grew in size and people migrated to different parts, via rail, road and sea, because of improvement in transport system, example the new lands in...