Environmental Pollution

The Indian Vulture and the Indian White-rumped Vulture, G. bengalensis species have suffered a 97%–99% population decrease in Pakistan and India, and between 2000-2007 annual decline rates of this species and the Slender-billed Vulture averaged over 16%. The cause of this has been identified as poisoning caused by the veterinary drug diclofenac. Diclofenac is a non-steroidal anti-inflammatory drug (NSAID) and when given to working animals it can reduce joint pain and thus, can keep them working for longer.

The discharge of heated water into a waterway often causes ecological imbalance, sometimes resulting in major fish kills near the discharge source. The increased temperature accelerates chemo-biological processes and decreases the ability of water to hold dissolved oxygen. Thermal changes affect the aquatic system by limiting or changing the type of fish and aquatic biota that is able to grow or reproduce in the waters.

Although essential to the aquatic habitat, nutrients such as nitrogen and phosphorus may also cause over fertilisation and accelerate the natural ageing process (eutrophication) of lakes. This acceleration in turn produces an overgrowth of aquatic vegetation, massive algal blooms and an overall shift in the biologic community from low productivity with many diverse species to high productivity with large numbers of a few species of a less desirable nature.

A point source of pollution is a single identifiable source of air, water, thermal, noise or light pollution.
A point source has negligible extent, distinguishing it from other pollution source geometries.
Nonpoint source (NPS) pollution refers to both water and air pollution from diffuse sources. Nonpoint source water pollution affects a water body from sources such as polluted run-off from agricultural areas draining into a river or wind-borne debris blowing out to sea.

The Great Smog of 1952, was a severe air pollution event that affected London during December 1952. A period of cold weather, combined with an anticyclone and windless conditions, collected airborne pollutants mostly from the use of coal to form a thick layer of smog over the city. It lasted from Friday 5 to Tuesday 9 December 1952, and then dispersed quickly after a change of weather. It left 4000 dead and another 100000 ill. 

Stockholm Convention on Persistent Organic Pollutants is an international environmental treaty, signed in 2001 and effective from May 2004, which aims to eliminate or restrict the production and use of persistent organic pollutants (POPs).

Although the frequency (pitch) of noise may be of major importance, most noise sources are measured in terms of intensity or strength of the sound field. The standard unit, one decibel (dB), is the amount of sound that is just audible to the average human. The decibel scale is somewhat misleading because it is logarithmic rather than linear. For example, a noise source measuring 70 dB is 10 times as loud as a source measuring 60 dB and 100 times as loud as a source reading 50 dB.

A global pollutant refers to a pollutant whose damage is determined by its concentration in the upper atmosphere. Examples:

1. Carbon dioxide is often cited as a contributor to the greenhouse effect.
2. Chloroflourocarbon emissions are linked to ozone depletion.

The absorptive capacity refers to the environment's ability to absorb waste products. If emissions exceed the absorptive capacity of the system, they will accumulate in the environment and cause damage. A stock pollutant is a pollutant for which the environment has little or no absorptive capacity.

Brownfields are abandoned or underused industrial and commercial facilities available for reuse. Expansion or redevelopment of such a facility may be complicated by real or perceived environmental contaminations. The land may be contaminated by low concentrations of hazardous waste or pollution, and has the potential to be reused once it is cleaned up.

Nutrient pollution, a form of water pollution, refers to contamination by excessive inputs of nutrients. It has the following effects:

Population effects: excess growth of algae (blooms);
Community effects: species composition shifts (dominant taxa);
Ecological effects: foodweb changes, light limitation;
Biogeochemical effects: excess organic carbon (eutrophication); dissolved oxygen deficits (hypoxia); toxin production;
Human health effects: excess nitrate in drinking water

Hypoxia refers to low oxygen conditions. Oxygen depletion is a phenomenon that occurs in aquatic environments as dissolved oxygen (DO; molecular oxygen dissolved in the water) becomes reduced in concentration to a point where it becomes detrimental to aquatic organisms living in the system. Oxygen depletion can result from a number of natural factors, but is most often a concern as a consequence of pollution and eutrophication in which plant nutrients enter a river, lake or ocean, and phytoplankton blooms are encouraged. While phytoplankton, through photosynthesis, will raise DO saturation during daylight hours, the dense population of a bloom reduces DO saturation during the night by respiration.

The Great Pacific garbage patch, also described as the Pacific trash vortex, is a gyre of marine debris in the central North Pacific Ocean located roughly between 135°W to 155°W and 35°N and 42°N. The patch is characterized by exceptionally high concentrations of pelagic plastics, chemical sludge and other debris that have been trapped by the currents of the North Pacific Gyre. The garbage patch occupies a large and relatively stationary region of the North Pacific Ocean bound by the North Pacific Gyre (a remote area commonly referred to as the horse latitudes).

The Ministry of Environment and Forests came into being in 1985. This ministry is the central administrative organisation in India for regulating and ensuring environmental protection.

The Dobson unit (DU) is a unit of measurement of the columnar density of a trace gas in the Earth's atmosphere. It originated and continues to be widely used as a measure of total-column ozone, which is dominated by ozone in the stratospheric ozone layer.