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Increase in the level of green house gases has led to heating of earth leading to global warming/ melting of glaciers/ rise in sea level that can flood the coastal areas.

Greenhouse gases other than CO₂

Methane (CH₄), CFCs chlorofluorocarbon, N₂O

CO₂ (40%) and CH₄ (20%) are the two gases which are contributing the maximum to green house effect.

(a) El Nino effect : El Nino is a severe atmospheric and oceanic disturbance in the pacific.Ocean that occurs every seven to fourteen years. It is called El Nino, meaning 'the Child', because it usually appears near the Christmas season. Warm surface waters flow from the central Pacific towards eastern Pacific. 

So El Nino is what the geo engineering study focussed on. Also because El Ninos are actually thought to be potentially more damaging on global scale, as they may cause floods and mudslides in Latin America, but also month-long drought in Southeast Asia and Australia through man-lit Borneo forest fires also causing environmental damage with increased CO₂ emission and biodiversity loss.

(b) The three measures that we as an individual would take to reduce environmental pollution are :

(i) Electrostatic precipitator : It is the most widely used method for removal of particulate matter; about 99% of particulate pollutants are removed by this method from the exhaust of a thermal power plant. 

(ii) Scrubber : Water dissolves the gases and lime reacts with sulphur dioxide to form a precipitate of calcium sulphate or sulphite. 

(iii) Catalytic converters : As the exhaust passes through the catalytic converter, unburnt hydrocarbons are converted into carbon dioxide and water, and carbon monoxide and nitric oxide are changed into carbon dioxide and nitrogen gas, respectively.

DDT being a toxic substance gets accumulated in the organism and passes on to the next higher trophic level because it cannot be metabolised or excreted. Thus, concentration of DDT has increased in the birds in the given case. The high concentration of DDT disturbs the calcium metabolism in birds, causes thinning of eggshells, their premature breaking and eventually causes a decline in the bird population.

The phenomenon is called biomagnification.

Radioactive wastes: Radioactive wastes such as uranium, are used as fuel in the atomic power plant. The accidental leakage and disposal of radioactive wastes are the most serious problems. All safety measures for this purpose should be strictly enforced. Highlevel radioactive wastes generate a lot of heat and thus require cooling, as well as special protective shield during handling and transport. Radiation, that is given off by nuclear wastes is extremely harmful to the organisms, because it causes mutation at a very high rate. At high doses, nuclear radiation is lethal but at lower doses, it creates various disorders, the most frequent of all being cancer. Therefore, nuclear waste is an extremely potent pollutant and has to be dealt with utmost caution.

Agriculture , composting , dairy management , beekeeping, water harvesting.

Conventional sedimentation, filtering and chlorine treatment. Absorption and assimilation of pollutants by algae fungi and bacteria. 

"Ecosan‘ derived from ecological sanitation. Handling human excreta using dry composting toilets. Its practical, hygienic and cost effective method.

(1) Cutting down use of fossil fuel 

(2) limproving efficiency of energy usage 

(3) Reducing deforestation 

(4) Planting trees and slowing down the growth of human population.

There are great apprehensions in using nuclear energy because of accidental leakages and finding ways for safe disposal of radioactive waste.

Accidental leakages, safe disposal of radioactive waste.

1. Eutrophication refers to the nutrient enrichment in water bodies leading to lack of oxygen and will end up in the death of aquatic organisms.

2. Algal Bloom is an excess growth of algae due to abundant excess nutrients imparting distinct color to water.

150 dB or more 

PM 2.5 stands for particulate matter of size 2.5 micrometers or less in diameter. Its responsible for causing greatest harm to human health as it can be inhaled deep into lungs and cause breathing problems.

The plant growing near the boundary wall act as barrier for sound pollution and act as dust catchers.

The National Forest Commission of India recommended a relatively larger forest cover for hills than for plains to reduce the chances of landslides.

The colourful polystyrene and plastic packaging are non-biodegradable and nonecofriendly.

At the beginning of the twentieth century, forests covered about 30 % of the land of India. By the end of the century, it shrunk to 19.4 %, whereas the National Forest Policy (1988) of India has recommended 33 % forest cover for the plains and 67 % for the hills.

Deforestation is caused due to human activation for following purposes.

• Forests are cleared for making homes and industries due to over population.
• Forests are converted into agricultural land to produce food for increasing population.
• Trees are fell for timber, firewood and other uses.

The Montreal Protocol was signed to control the emission of ozone depleting substances. Excessive use of CFCs and other ozone depleting chemicals has resulted in thinning of ozone layer. Further thinning would allow harmful UV-B radiations to enter Earth’s atmosphere and have deleterious effects on living organisms.

Causes of deforestation are

• Conversions of forest land to agricultural land to produce food for* increasing population.
• Cutting of trees for timber and wood
• Jhumcultivation in the north-eastern states of India
• Forest fires.

(b) Montreal and Kyoto protocols.

(b) Atmosphere

(a) A catalytic converter is a device that converts toxic gases and pollutants into less toxic pollutants by catalyzing redox reaction.

(b) Gases that trap the heat within the atmosphere are called Green house gases. 

Example: CO₂ and CO

(c) About 150 liters of wastewater at an average is generated by an Indian individual daily, and a large amount of it is generated from toilets. Ecological sanitation (EcoSan) is a sustainable system for handling human excreta by using dry composting toilets. EcoSan toilets not only reduce wastewater generation but also generate the natural fertiliser from recycled human excreta, which forms an excellent substitute for chemical fertilisers. This method is based on the principle of recovery and recycling of nutrients from excreta to create a valuable supply for agriculture.

The ‘Forest man of India Jadav Payeng who created 1,360 acres of dense and defiant forest was bom in Arunasapori (a river island on the Brahmaputra). He had just completed his Class X exams in 1979 when he started-to sow the seeds and shoots on the eroded island covered with sand and silt.

Thirty-six years later he had converted the once unproductive land into a forest. Payeng’s forest is now home to five Royal Bengal tigers, over a hundred deer, wild boar, vultures, and several species of birds. For his remarkable initiative, the Jawaharlal Nehru University invited Payeng in 2012 on Earth Day and honoured him with the title of the ‘Forest Man of India’.