Mosses are a common flowerless plant found in all cities especially in damp (humid) or shady locations. It generally absorbs water and nutrients from their immediate environments. So, according to scientists, delicate mosses found on rocks and trees in cities around the world can be used as low-cost bio indicator to monitor urban pollution and to measure the impact of atmospheric change. As a bio indicator, mosses respond to pollution or drought-stress by changing its shape, density or
disappearing.

Most of the organic toxins are water insoluble and non-biodegradable.
These high persistent toxins are, therefore, transferred from lower trophic level to higher trophic level through food chain.
Over time, the concentration of toxins in higher animals reaches a level which causes serious metabolic and physiological disorders

Types of biotic interaction:
Mutualism: both species benefit, Example: in pollination mutualisms, the pollinator gets food (pollen, nectar), and the plant has its pollen transferred to other flowers for cross-fertilization (reproduction).
Commensalism: one species benefits, the other is unaffected. Example: cow dung provides food and shelter to dung beetles. The beetles have no effect on the cows.
Competition: both species are harmed by the interaction. Example: if two species eat the same food, and there
isn’t enough for both, both may have access to less food than they would if alone. They both suffer a shortage of food.
Predation and parasitism: one species benefits, the other are harmed. Example: predation-one fish kills and eats. Parasitism: tick gains benefit by sucking blood; host is harmed by losing blood.
Amensalism: One species is harmed, the other is unaffected. Example: A large tree shades a small plant, retarding the growth of the small plant. The small plant has no effect on the large tree.

The following pollutants are emitted from motor vehicles:
Particulate matter (PM).
Un-burnt hydrocarbons.
Nitrogen oxides (NOx).
Carbon monoxide (CO).
Carbon dioxide (CO2).
Sulphur dioxide (SO2).
Methane
While ozone is not emitted directly from automobiles, the unstable compound is formed in the atmosphere through a complex set of chemical reactions involving hydrocarbons, oxides of nitrogen, and sunlight.

The Global Tiger Initiative (GTI) was launched in 2008 as a global alliance of governments, international organizations, civil society, the conservation and scientific communities and the private sector, with the aim of working together to save wild tigers from extinction. In 2013, the scope was broadened to include Snow Leopards.
The GTI’s founding partners included the World Bank, the Global Environment Facility (GEF), the Smithsonian Institution, Save the Tiger Fund, and International Tiger Coalition (representing more than 40 non-government organizations). The initiative is led by the 13 tiger range countries (TRCs).
In November 2010, leaders of the tiger range countries (TRCs) assembled at an International Tiger Forum in St. Petersburg, Russia to adopt the St. Petersburg Declaration on Tiger Conservation and endorsed its implementation mechanism, called the Global Tiger Recovery Program. Their overarching goal was to double the
number of wild tigers across their geographical area from about 3,200 to more than 7,000 by 2022.