What do you think is the greatest contributor of pollution in your country?  

The litter you refer is very visible and quite an eyesore. The greatest source of pollution in the US is from the transportation vehicles. These have not had as much regulation yet. Many would say industry, but industry is already very heavy regulated. People make pollution, and most people do not want to change their lifestyle to avoid it.

i think in india its cars

i can say it is the smoke coming from vehicles and factories. those pollutants are the ones i consider as doing the greatest damage to our environment. garbage do pollute rivers but i think it does not really contaminate the water. untreated water coming out from factories or plants does more harm to our rivers.

Immature people !!!"the greatest contributor of pollution" as u term it !

The major forms of pollution in my country:
air pollution,is cause by burned of forrest, the release of chemicals and particulates into the atmosphere. Common examples include carbon monoxide, sulfur dioxide, chlorofluorocarbons (CFCs), and nitrogen oxides produced by industry and motor vehicles. Ozone and smog are created as nitrogen oxides and hydrocarbons react to sunlight.
Water pollution is come from the industry via surface runoff and leaching to groundwater.
Soil contamination occurs when chemicals are released by spill or underground storage tank leakage. Among the most significant soil contaminants are hydrocarbons, heavy metals, MTBE, herbicides, pesticides and chlorinated hydrocarbons.

yes. plastic carry bags are greatest threat to nature.