[Anjana]

Gases that trap heat in the atmosphere are called greenhouse gases. The major Greenhouse gases includes,

1) Carbon dioxide (CO2) :-

Carbon dioxide enters the atmosphere through burning fossil fuels (coal, natural gas, and oil), solid waste, trees and other biological materials, and also as a result of certain chemical reactions (e.g., cement production). Carbon dioxide is removed from the atmosphere (sequestered) when it is absorbed by plants as part of the biological carbon cycle.

2) Methane (CH4) :-

Methane is emitted during the production and transport of coal, natural gas, and oil. Methane emissions also result from livestock and other agricultural practices, land use, and by the decay of organic waste in municipal solid waste landfills.

3) Nitrous Oxide (N2O):-

Nitrous oxide is emitted during agricultural, land use, and industrial activities; combustion of fossil fuels and solid waste; as well as during treatment of wastewater.

4) Fluourinated gases :-

Hydrofluorocarbons, perfluorocarbons, sulfur hexafluoride, and nitrogen trifluoride are synthetic, powerful greenhouse gases that are emitted from a variety of household, commercial, and industrial applications and processes. Fluorinated gases (especially hydrofluorocarbons) are sometimes used as substitutes for stratospheric ozone-depleting substances (e.g., chlorofluorocarbons, hydrochlorofluorocarbons, and halons). Fluorinated gases are typically emitted in smaller quantities than other greenhouse gases, but they are potent greenhouse gases.

Effect of Greenhouse gases on the Atmosphere:-

1. They traps the heat in the atmosphere and leads to global warming (temperature rise).

2. Causes ozone depletion

3. Results in acid rain ( occurs when these gases and its compounds mixes in rainwater and show acidic nature).

[Anjana]

In the year 1911 Calcutta became the former capital of British India and it was shifted to Delhi, in 1914. The decision was taken during the reign of Lord Hardinge, the then Viceroy of India. Delhi was the financial and political seat of many earlier empires and was located closer to the geographical center of India. The rising nationalist movement in Calcutta was also responsible for the shift.