Geography
The Islamic Republic of Pakistan spreads over 796 100 km2 between latitudes 24 and 27° N and longitudes 61 and 75° E. Afghanistan bounds it on the north-west; Iran on the west; Russia and China on the north; India on the east; and the Arabian Sea on the south. The country can be divided into three main geographical regions:
- The mountains occupy the northern and western parts of the country. The northern mountains are the termination of the Himalayan range with a number of peaks well above 6 000 m permanently clad with snow. The sub-mountainous areas are extensive, forming a number of plateaus and valleys. The western mountains are not very high and are associated with plateaus, semi-arid valleys and plains, most of which are unproductive;
- The Indus plain is the western part of the indo-gangetic plain that forms one of the most prominent and extensive physiographic features of the subcontinent. The plain is believed to be more than one thousand meters deep and is formed by large quantities of alluvial material deposited since time immemorial by the Indus and several of its tributaries. The land is fertile and heavily populated;
- The coastal zone is a narrow fringe bordering the Arabian Sea. It includes also the Indus delta and the saline marshes of the Rann of Kutch.
The climate of the country, which lies in the subtropical region, is varied due to the wide range of altitude and distance to sea. In the mountain regions of the north and west, temperatures fall below freezing during winter; in the Indus Valley area, temperatures range between about 32° and 49° C in summer and the average about 13° C in winter.
The larger part of the country is situated in the arid and semi-arid zones. Part of the precipitation in the high hills is received in the form of snow. Lower down, the annual rainfall averages between 750 and 900 mm, decreasing progressively to the west and south to as low as 125 mm in certain areas.
The climate is considerably influenced by monsoon winds that come from the south-east in summer and by cyclonic disturbances that originate in the Mediterranean Sea during winter. About 70 percent of the average precipitation is received from June to September. The difference in temperature between the seasons is relatively high.
Most of the hilly area is denuded and has little soil left. Sub-mountainous plateaus and the adjoining plains have well drained alluvial soils and part of the corresponding agriculture land is very fertile. The Indus plain is composed of silt, sand, clay and, rarely, gravel. Much of the land in this basin was desert and has been developed by irrigation. Due to arid conditions, evaporation exceeds precipitation and this may result in the accumulation of salt in the soils, rendering them less productive.