Photo-chemical smog is also known to have adverse effect on plants both within cities and also on their outskirts.
Soil is the most vulnerable of human resource and is one on which humans have had a very major impact, because they lie close to and depend an the soil.
Impact on soil can occur with great rapidity in response to land use change by new technologies.
Salinity is a natural characteristicis in semi-arid and arid soils.
Water is the source of life and right from the origin, human beings are using it for various purposes.
The ancient civilizations have developed in river valley.
Earlier, the influence of human activity on water resources was limited but now this has become a major problem of environmental degradation throughout the world.
The consideration of dams and reservoirs is widespread throughout the world for irrigation purpose, to generate power or to provide a reliable source of water.
There are many ways in which humans can alter this, especially by compacting it with agricultural machinery and by changing its chemical character through irrigation.
Grazing is another activity that can damage soil structure through trampling and compaction.