Asked/Added Questions From NCERT:

 “Potable water” simply means water that is safe to drink, and it is becoming scarcer in the world Increasing use is stressing freshwater resources worldwide, and a seemingly endless list of contaminants can turn once potable water into a health hazard or simply make it unacceptable aesthetically.

-Answered by Hitesh kumar On 20 April 2019:08:04:54 AM

 Co₂ gas is most responsible for Global Warming. 

-Answered by Himanshi Verma On 21 April 2019:10:39:02 AM

 Economic water scarcity is caused by a lack of investment in infrastructure or technology to draw water from rivers, aquifers or other water sources, or insufficient human capacity to satisfy the demand for water. One quarter of the world's population is affected by economic water scarcity.

-Answered by Himanshi Verma On 21 April 2019:10:39:14 AM

 Air pollution is defined as the introduction of pollutants, organic molecules, or other unsafe materials into Earth’s atmosphere. This can be in the form of excessive gases like carbon dioxide and other vapours that cannot be effectively removed through natural cycles, such as the carbon cycle or the nitrogen cycle.

-Answered by Himanshi Verma On 21 April 2019:10:39:27 AM

 Chemical waste from factories is sometimes dumped into rivers and lakes, or directly into the ground. Pesticides (chemicals that kill insects) applied to farmland enter surface water and groundwater, often in large quantities. Once a pollutant enters a water supply, it is difficult to get rid of it.

-Answered by Himanshi Verma On 21 April 2019:10:39:38 AM

 Carbon dioxide (CO. ...

Methane (CH. ...

• Nitrous oxide (N. ₂O)
• Ozone (O. ...
• Chlorofluorocarbons (CFCs)
• Hydrofluorocarbons (incl. HCFCs and HFCs)

-Answered by Hitesh kumar On 20 April 2019:10:00:10 AM

  Greenhouse gas, any gas that has the property of absorbing  emitted from Earth’s surface and reradiating it back to Earth’s surface, thus contributing to the green house effect. carbon dioxide and methane and water vapour are the most important greenhouse gases. (To a lesser extent, surface-level  fluorinated gases also trap infrared radiation.) Greenhouse gases have a profound effect on the energy. budget of the Earth system despite making up only a fraction of all atmospheric gases. Concentrations of greenhouse gases have varied substantially during Earth’s history, and these variations have driven substantial climate changes. at a wide range of timescales. In general, greenhouse gas concentrations have been particularly high during warm periods and low during cold periods.

-Answered by Himanshi Verma On 21 April 2019:10:39:54 AM