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GS Paper: GS1

  • Commonwealth adopts ‘Living Lands Charter’

    All 54 Commonwealth members have agreed to voluntarily dedicate a ‘living land’ in their respective countries to future generations, in line with the strategy set for the UN Decade on Ecosystem Restoration.

    Living Lands Charter

    • The non-binding mandates that member countries will safeguard global land resources and arrest land degradation while acting against climate change, biodiversity loss and sustainable management.
    • It helps to encapsulate the combined effort to hold the global average temperature increase to 1.5 degrees Celsius, said Commonwealth Secretary-General Patricia Scotland.
    • The document came after nearly two years of intense consultation, engagement and negotiation with member countries at UN Rio Convention.

    Key objectives

    • Leaders and their representatives noted with concern in the charter the alarming decline in the health and productivity of global land resources.
    • It aimed to support member countries to effectively deliver their commitments under the three Rio conventions:
    1. UN Convention on Biological Diversity
    2. UN Convention to Combat Desertification (UNCCD)
    3. UN Framework Convention on Climate Change

    Major outcomes

    • The attendees also underlined the principle of “critical guardianship” provided by indigenous peoples and local communities in protecting land and vital ecosystem services.
    • The agreement was released along with a final wide-ranging communiqué by leaders, including on specific items on climate change.
    • Country heads underscored in it that the “urgent threat of climate change” exacerbates existing vulnerabilities and presents a significant threat to COVID-19 recovery efforts.

     

    Try this PYQ from CSP 2012:

    Q.Consider the following statements:

    1. The Commonwealth has no charter, treaty or constitution
    2. All the territories/countries once under the British Empire (jurisdiction/rule/mandate) automatically joined the Commonwealth as its members

    Which of the statements given above is/are correct?

    (a) 1 only

    (b) 2 only

    (c) Both 1 and 2

    (d) Neither 1 nor 2

     

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    Back2Basics: Commonwealth of Nations

    • The Commonwealth of Nations is an intergovernmental organisation of 53 member states that are mostly former territories of the British Empire.
    • It dates back to the first half of the 20th century with the decolonization of the British Empire through increased self-governance of its territories.
    • It was originally created as the British Commonwealth of Nation through the Balfour Declaration at the 1926 Imperial Conference, and formalized by the UK through the Statute of Westminster in 1931.
    • The current body was formally constituted by the London Declaration in 1949, which modernized the community, and established the member states as “free and equal”.
    • The symbol of this free association is Queen Elizabeth II, who is the Head of the Commonwealth.
    • The Queen is head of state of 16 member states, known as the Commonwealth realms, while 32 other members are republics and five others have different monarchs.
    • Member has no legal obligations to one another. Instead, they are united by language, history, culture and their shared values of democracy, human rights and the rule of law.

     

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  • Centre asks firms to arrange Tricolours

    Independence Day 2020 | Independence Day: Facts about Indian tricolour that you may have missed | India News

    The Centre has reached out to manufacturers and e-commerce sites to boost the availability of the Tricolour, according to officials aware of the programme.

    Why in news?

    • The Centre is set to launch a large-scale campaign to encourage Indians to fly the National Fag at their homes to mark the 75th Independence Day.
    • The aim of the campaign was to inspire people, rather than carry out a distribution drive.

    How is it made possible?

    • In order to facilitate the campaign, the Union Home Ministry had last year amended the Flag Code, which earlier only allowed hand-woven or hand-spun flags to be made.
    • It has now allowed flags to be polyester and machine-made.

    Do you know?

    Earlier, the display of the national flag was governed by the provisions of The Emblems and Names (Prevention of Improper Use) Act, 1950 and the Prevention of Insults to National Honour Act, 1971.

    What is the Flag Code of India?

    • The Flag Code of India is a set of laws, practices and conventions that apply to the display of the national flag of India.
    • The Code took effect from 26 January 2002 and superseded the “Flag Code-India” as it existed earlier.
    • It permits the unrestricted display of the tricolour, consistent with the honour and dignity of the flag.

    The Flag Code of India has been divided into three parts:-

    • First Part: General Description of the National Flag.
    • Second Part: Display of the National Flag by members of public, private Organisations & educational institutions etc.
    • Third Part: Display of National Flag by Union or State Governments and their organisations and agencies.

    Disposing of the national flag

    • A/c to the Flag Code, such paper flags are not to be discarded or thrown on the ground after the event.
    • Such flags are to be disposed of, in private, consistent with the dignity of the flag.

    Hoisting the national flag is a fundamental right

    • The bench headed by Chief Justice of India V. N. Khare said that under Article 19(1)(a) of the Constitution of India, citizens had the fundamental right to fly the national flag on their premises throughout the year.
    • However, it provided that the premises do not undermine the dignity of the national flag.

    About Prevention of Insults to National Honour Act

    • The law, enacted on December 23, 1971, penalizes the desecration of or insult to Indian national symbols, such as the National Flag, the Constitution, the National Anthem, and the Indian map, as well as contempt of the Constitution of India.
    • Section 2 of the Act deals with insults to the Indian National Flag and the Constitution of India.

    Do you know?

    Article 51 ‘A’ contained in Part IV A i.e. Fundamental Duties asks:

    To abide by the constitution and respect its ideals and institutions, the National Flag and the National Anthem in clause (a).

    Back2Basics: Story of our National Flag

    (1) Public display for the first time

    • Arguably the first national flag of India is said to have been hoisted on August 7, 1906, in Kolkata at the Parsee Bagan Square (Green Park).
    • It comprised three horizontal stripes of red, yellow and green, with Vande Mataram written in the middle.
    • Believed to have been designed by freedom activists Sachindra Prasad Bose and Hemchandra Kanungo, the red stripe on the flag had symbols of the sun and a crescent moon, and the green strip had eight half-open lotuses.

    (2) In Germany

    • In 1907, Madame Cama and her group of exiled revolutionaries hoisted an Indian flag in Germany in 1907 — this was the first Indian flag to be hoisted in a foreign land.

    (3) During the Home Rule Movement

    • In 1917, Dr Annie Besant and Lokmanya Tilak adopted a new flag as part of the Home Rule Movement.
    • It had five alternate red and four green horizontal stripes, and seven stars in the saptarishi configuration.
    • A white crescent and star occupied one top corner, and the other had Union Jack.

    (4) Final version by Pingali Venkayya

    • The design of the present-day Indian tricolour is largely attributed to Pingali Venkayya, an Indian freedom fighter.
    • He reportedly first met Mahatma Gandhi in South Africa during the second Anglo-Boer War (1899-1902), when he was posted there as part of the British Indian Army.
    • Years of research went into designing the national flag. In 1916, he even published a book with possible designs of Indian flags.
    • At the All India Congress Committee in Bezwada in 1921, Venkayya again met Gandhi and proposed a basic design of the flag, consisting of two red and green bands to symbolise the two major communities, Hindus and Muslims.

    (5) During Constituent Assembly

    • On July 22, 1947, when members of the Constituent Assembly of India, the first item on the agenda was reportedly a motion by Pandit Nehru, about adopting a national flag for free India.
    • It was proposed that “the National Flag of India shall be horizontal tricolour of deep saffron (Kesari), white and dark green in equal proportion.”
    • The white band was to have a wheel in navy blue (the charkha being replaced by the chakra), which appears on the abacus of the Sarnath Lion Capital of Ashoka.

     

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  • Festival in news: Sao Joao Festival

    As in every monsoon, Catholics in Goa will celebrate Sao Joao, the feast of St John the Baptist.

    Note: The name typically sounds like a North-Eastern festival, but it is not.

    What is Sao Joao and where is it celebrated in Goa?

    • In Goa, Catholics celebrate all the feasts of the Roman Catholic Church, which include the feast of St John the Baptist on June 24.
    • John the Baptist is the person who he had baptised Jesus Christ on the river Jordan.
    • Traditionally, there are spirited Sao Joao festivities in the villages of Cortalim in South Goa and Harmal, Baga, Siolim and Terekhol in North Goa.
    • However, over the years, pool parties and private Sao Joao parties in Goa have been a “complete package of merriment and joy” for tourists.

    Course of celebration

    • The celebrations will include revellers sporting crowns made of fruits, flowers and leaves, and the major draw of the feast is the water bodies – wells, ponds, fountains, rivers – in which the revellers take the “leap of joy”.
    • Enjoyed by children and adults alike, the festival also includes playing the traditional gumott (percussion instrument), a boat festival, servings of feni, and a place of pride for new sons-in-law.

    What does jumping into water bodies symbolise?

    • The youngsters in Goa celebrate this occasion with revelry and perform daredevil feats, by jumping into over flowing wells or rivulets.
    • The boys are found merrily jumping into the water to commemorate the leap of joy, which St John is said to have taken in the womb of his mother St Elizabeth when virgin Mary visited her.

     

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  • Odisha’s Mo Bus: Recipient of the UN’s prestigious public service award

    Mo Bus, the bus service of Odisha’s Capital Region Urban Transport (CRUT) authority, has been recognized by the United Nations as one of 10 global recipients of its annual Public Service Awards for 2022.

    Mo Bus service

    • The Mo Bus service was launched on November 6, 2018.
    • It aimed to ensure transformation of the urban public transport scenario in the city and its hinterland through use of smart technology, service benchmarking and customer satisfaction.
    • The buses are designed to integrate smart technologies such as free on-board Wi-Fi service, digital announcements, surveillance cameras, and electronic ticketing.
    • CRUT says that to increase women’s participation in the workforce, and to make women riders feel safer, it is committed to ensuring that 50% of Mo Bus Guides (conductors) are women.

    What is the recent award?

    • The public transport service has been recognised for its role in “promoting gender-responsive public services to achieve the SDGs (Sustainable Development Goals)”.
    • The “impact” is that 57 per cent of the city’s commuters now use the Mo Bus, the UN said.
    • Mo E-Ride is estimated to reduce pollution by 30-50 per cent.

    About UN Public Service Award

    • The UN describes its Public Service Awards as the “most prestigious international recognition of excellence in public service”.
    • The first Awards ceremony was held in 2003, and the UN has since received “an increasing number of submissions from all around the world”.
    • It is intended to reward the creative achievements and contributions of public service institutions that lead to a more effective and responsive public administration in countries worldwide.
    • Through an annual competition, the UN Public Service Awards promotes the role, professionalism and visibility of public service.

     

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  • Tribes in news: Santhal Tribe

    The Santhal community is in the spotlight after a political alliance nominated one of its leaders for the Presidential election, Droupadi Murmu, for the election to the highest Constitutional post of India.

    Santhal Tribe

    • Santhal, also spelt as Santal, literally means a calm, peaceful man. Santha means calm, and ala means man in the Santhali (also spelt as Santali) language.
    • Santhals are the third largest Scheduled Tribe community in India after Gonds and Bhils.
    • The Santhali population is mostly distributed in Jharkhand, Odisha and West Bengal.

    Historical background

    • The Santhals were a nomadic stock before they chose to settle in the Chotanagpur plateau.
    • By the end of the 18th century, they had concentrated in the Santhal Parganas of Jharkhand (earlier Bihar).
    • From there, they migrated to Odisha and West Bengal.

    Demographic details

    • Tribal communities, outside the Northeast, generally have lower levels of literacy.
    • But the Santhals have higher – a result of a pro-school education awareness since at least the 1960s – literacy rate compared to other tribes in Odisha, Jharkhand and West Bengal.
    • Many of the community have entered the creamy layer of Indian society.
    • For example, Jharkhand CM Hemant Soren is a Santhal.
    • The incumbent Comptroller and Auditor General of India (CAGI) Girsh Chandra Murmu, who was the first Lt Governor of the UT of Jammu and Kashmir, is also a Santhal.

    Cultural features of Santhals

    (1) Religion

    • Despite their social upliftment, the Santhals are usually connected to their roots.
    • They are nature worshippers and could be seen paying obeisance at Jaher (sacred groves) in their villages.
    • River Damodar holds a special place in the religious life cycle of a Santhal.
    • When a Santhal dies, his or her ashes and bones are immersed in the Damodar for a peaceful afterlife.
    • Their traditional dress includes dhoti and gamuchha for men and a short-check saree, usually blue and green, for women, who generally put on tattoos.

     (2) Society

    • Various forms of marriage are accepted in the Santhal society – including elopement, widow remarriage, levirate, forced (rare) and the one in which a man is made to marry the woman he has impregnated.
    • Divorce is not a taboo in the Santhal society. Either of the couple could divorce the other.

    (3) Artforms

    • Santhals are fond of their folk song and dance that they perform at all community events and celebrations.
    • They play musical instruments like kamak, dhol, sarangi and flutes.
    • Most Santhals are agriculturists, depending on their farmlands or forests.
    • Their homes, called Olah, have a particular three-colour pattern on the outer walls.
    • The bottom portion is painted with black soil, the middle with white and the upper with red.

    (4) Language

    • Their tribal language is called Santhali, which is written in a script called Ol chiki, developed by Santhal scholar Pandit Raghunath Murmu.
    • Santhali language belongs to the Munda group.
    • Santhali written in OI-Chiki script is recognised as one of the scheduled languages in the Eighth Schedule to the Constitution.

    Back2Basics: Santhal Rebellion

    • The Santhal rebellion also known as Santhal Hool was a revolt by the Santhal in present-day Jharkhand, India, against the British East India Company and the Zamindari System.
    • It began on June 30, 1855, and the East India Company declared martial law on November 10, 1855, which lasted until January 3, 1856, when martial law was lifted.
    • The insurrection was put down by the Presidency soldiers.
    • The four Murmu Brothers – Sidhu, Kanhu, Chand, and Bhairav – spearheaded the revolt.

     

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  • Judicial Validity of the Talaq-e-Hasan mode of Divorce

    A public interest litigation (PIL) seeking to invalidate Talaq-e-Hasan, the prescribed Islamic way of divorce, has been filed in the Supreme Court.

    What is the PIL about?

    • The petition seeks to make the prescribed Islamic way of divorce Talaq-e-Hasan unconstitutional as it is violative of Articles 14, 15, 21 and 25 of the Constitution.
    • The petitioner has been unilaterally divorced through the Talaq-e-Hasan mode by her husband.
    • She also prayed that Section 2 of the Muslim Personal Law (Shariat) Application Act, 1937 that permits Muslims to practise unilateral divorce be declared void.

    Basis of the PIL

    • The hearing comes almost five years after the five judge Bench headed by then CJI J.S. Khehar invalidated instant triple talaq in their verdict in the Shayara Bano vs the Union of India Case.
    • The invalidation of instant triple talaq where the court held, “What is bad in theology is bad in law as well”, led to the enactment of the Muslim Women (Protection of Rights on Marriage) Act 2019.

    What is Triple Talaq?

    • In instant triple talaq a man pronounces multiple divorce in one go.
    • It has no scope for reconciliation between the feuding couple, and often ends a marriage instantly.
    • It is, as the judges held, not mentioned anywhere in the Quran which prescribes a code of divorce largely through Surah Baqarah, verses 226 to 237 and the opening six verses of Surah Talaq.
    • Incidentally, triple talaq in this manner has been banned in many Muslim countries, including Egypt, Pakistan, Jordan, Kuwait, Iraq, Malaysia etc.

    How is Talaq-e-Hasan different from instant triple talaq?

    • Unlike instant triple talaq, Talaq-e-Hasan is pronounced with a gap of at least one month or one menstrual cycle.
    • Only a single revocable divorce takes place through the first pronouncement of Talaq-e-Hasan.
    • The husband and wife are supposed to live together after this pronouncement and have the option of rapprochement.
    • If the couple is not able to mend fences in the intervening period and the husband does not annul divorce through word or by establishing intimacy, the talaq stays valid.
    • At the end of this month, the husband has to pronounce divorce for the second time.
    • Likewise for the third time. After the second pronouncement too, the divorce is revocable, and the couple may resume their conjugal relationship anytime they so desire.
    • If, however, the third pronouncement is made after at least one menstrual cycle, then irrevocable divorce takes place.

    Why such hue over menstrual cycle?

    • Significantly, no divorce can be administered when the woman is undergoing her menstrual cycle.
    • Even in the case of pregnancy, no divorce takes place.
    • And if such a pronouncement is made, it remains in abeyance till the end of pregnancy.

    Are there other options of divorce apart from the Talaq-e-Hasan?

    • The third option of divorce besides Talaq-e-Hasan and the now repudiated instant triple talaq, is Talaq-e-Ahsan.
    • Under this form, a single pronouncement is made.
    • Following the pronouncement, a woman has to go through iddat or a waiting period of three months.
    • During this period the divorce can be cancelled.
    • However, failure to annul divorce during this period results in it being finalised after which a woman is independent, and free to marry another man or stay single, as she may choose.
    • Both Talaq-e-Hasan and Talaq-e-Ahsan enjoy legal validity in almost all Muslim countries.
    • Interestingly, women too have a right to end an unsuccessful marriage through Khula.

    Legal status of Khula in India

    • In April 2021, the Kerala High Court held this form of divorce valid.
    • The court overruled a 49-year-old verdict in K.C. Moyin vs Nafeesa and Others (1972) that barred Muslim women from dissolving their marriage through non-judicial modes.
    • There is some debate among religious scholars on the ways of Khula.
    • Some hold that the man’s consent is necessary in Khula while most say that he enjoys no such privilege.

     

     

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  • Summer Solstice 2022: What is it and how is it significant?

    Yesterday, June 21 was the day of the summer solstice in the northern hemisphere.

    What is Summer Solstice?

    • Solstice means “sun stands still” in Latin.
    • The longest day of 2021 for those living north of the Equator is June 21.
    • This day is characterized by a greater amount of energy received from the sun.
    • In technical terms, this day is referred to as the summer solstice, the longest day of the summer season.
    • It occurs when the sun is directly over the Tropic of Cancer, or more specifically right over 23.5-degree north latitude.

    The Southern Hemisphere receives most sunlight on December 21, 22 or 23 when the northern hemisphere has its longest nights– or the winter solstice.

    Why do we have summer solstice?

    • Since Earth rotates on its axis, the Northern Hemisphere gets more direct sunlight between March and September over the course of a day.
    • This also means people living in the Northern Hemisphere experience summer during this time.
    • The rest of the year, the Southern Hemisphere gets more sunlight.
    • During the solstice, the Earth’s axis — around which the planet spins, completing one turn each day — is tilted in a way that the North Pole is tipped towards the sun and the South Pole is away from it.

    Answer this PYQ in the comment box:

    Q.On 21st June, the Sun (CSP 2019):

     

    (a) Does not set below the horizon at the Arctic Circle

    (b) Does not set below the horizon at Antarctic Circle

    (c) Shines vertically overhead at noon on the Equator

    (d) Shines vertically overhead at the Tropic of Capricorn

     

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    Some interesting facts

    • During the June solstice compared to any other time of the year, the North Pole is tipped more directly toward the sun, and the south pole is tipped more directly away from the sun.
    • As a result, all locations north of the equator see days longer than 12 hours and all locations south see days shorter than 12 hours.
    • The sun’s path across the sky is curved—NOT a straight line on the summer solstice.
    • Based on Earth’s current orbit, the summer solstice date rotates between June 20, 21 and 22 and is not fixed since it depends on the physics of our solar system and not on human calendar.

     

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  • Explained: Occurrence of Lightning

    At least 70 people died in lightning strikes across Uttar Pradesh, Madhya Pradesh and Rajasthan.

    What is lightning?

    • Scientifically, lightning is a rapid and massive discharge of electricity in the atmosphere some of which is directed towards earth.
    • The discharges are generated in giant moisture-bearing clouds that are 10-12 km tall.
    • The base of these clouds typically lie within 1-2 km of the Earth’s surface, while the top is 12-13 km away.
    • Temperatures in the top of these clouds are in the range of –35° to –45°C.

    Its formation

    • As water vapour moves upward in the cloud, the falling temperature causes it to condense.
    • As they move to temperatures below 0°C, the water droplets change into small ice crystals.
    • They continue to move up, gathering mass until they are so heavy that they start to fall to Earth.
    • This leads to a system in which, simultaneously, smaller ice crystals are moving up and bigger crystals are coming down.
    • Collisions follow and trigger the release of electrons, a process that is very similar to the generation of sparks of electricity.
    • As the moving free electrons cause more collisions and more electrons, a chain reaction ensues.
    • This process results in a situation in which the top layer of the cloud gets positively charged, while the middle layer is negatively charged.
    • The electrical potential difference between the two layers is huge, of the order of a billion to 10 billion volts.
    • In very little time, a massive current, of the order of 100,000 to a million amperes, starts to flow between the layers.

    Types of lightning

    • Broadly, there are three forms of lightning:
    1. Inter-cloud
    2. Intra-cloud
    3. Cloud-to-ground
    • It is the cloud-to-ground form of lightning that kills humans, as well as animals and livestock, and can substantially damage property.
    • While the Earth is a good conductor of electricity, it is electrically neutral.
    • However, in comparison to the middle layer of the cloud, it becomes positively charged.
    • As a result, about 15%-20% of the current gets directed towards the Earth as well.
    • It is this flow of current that results in damage to life and property on Earth.

    How intensely does it strike?

    • A typical lightning flash is about 300 million volts and 30,000 amps.
    • To put it in perspective, household current is 120 volts and 15 amps.
    • A flash of lightning is enough to light a 100-watt incandescent bulb for about three months.

    Why does lightning kill so many people in India?

    • The reason for the high number of deaths is due to people being caught unawares and more than 70% of fatalities happened due to people standing under isolated tall trees.
    • About 25 per cent of the people were struck in the open.
    • Also, lightning is the direct promulgation of climate change extremities.

    Mitigating lightning incidents

    • Lightning is not classified as a natural disaster in India.
    • But recent efforts have resulted in the setting up of an early warning system that is already saving many lives.
    • More than 96% of lightning deaths happen in rural areas.
    • As such, most of the mitigation and public awareness programmes need to focus on these communities.
    • Lightning protection devices are fairly unsophisticated and low-cost. Yet, their deployment in the rural areas, as of now, is extremely low.
    • States are being encouraged to prepare and implement lightning action plans, on the lines of heat action plans.
    • An international centre for excellence on lightning research to boost detection and early warning systems is also in the process of being set up.

     

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  • How Marine Heatwave fuelled super cyclone Amphan

    The super-cyclone Amphan is said to have been triggered by Marine Heatwaves.

    What is the news?

    • A study has found the presence of a strong MHW beneath the track of the cyclone with an extremely high anomalous sea surface temperature of more than 2.5°C.
    • This coincided with the cyclone track and facilitated its rapid intensification in a short period.

    What are Marine Heatwaves?

    • We know that heatwaves occur in the atmosphere. We are all familiar with these extended periods of excessively hot weather.
    • However, heatwaves can also occur in the ocean and these are known as marine heatwaves, or MHWs.
    • These marine heatwaves, when ocean temperatures are extremely warm for an extended period of time can have significant impacts on marine ecosystems and industries.

    When do they occur?

    • Heatwaves can happen in summer and also in winter, where they are known as “winter warm-spells”.
    • These winter events can have important impacts, such as in the southeast of Australia where the spiny sea urchin can only colonize further south when winter temperatures are above 12 °C.

    What causes marine heatwaves?

    • Marine heatwaves can be caused by a whole range of factors, and not all factors are important for each event.
    • The most common drivers of marine heatwaves include ocean currents which can build up areas of warm water and air-sea heat flux, or warming through the ocean surface from the atmosphere.
    • Winds can enhance or suppress the warming in a marine heatwave, and climate modes like El Niño can change the likelihood of events occurring in certain regions.
    • MHWs can be caused due to large-scale drivers of the Earth’s climate like the El Niño Southern Oscillation (ENSO).

    Impacts of the MHWs

    • Marine heatwaves affect ecosystem structure, by supporting certain species and suppressing others.
    • For example, after the 2011 marine heatwave in Western Australia, the fish communities had a much more “tropical” nature than previously and switched from kelp forests to seaweed turfs.
    • Marine heatwaves can cause economic losses through impacts on fisheries and aquaculture.
    • Temperature-sensitive species such as corals are especially vulnerable to MHWs. In 2016, marine heatwaves across northern Australia led to severe bleaching of the Great Barrier Reef.

    How do we measure marine heatwaves?

    • A marine heatwave occurs when seawater temperatures exceed a seasonally-varying threshold (usually the 90th percentile) for at least 5 consecutive days.
    • Successive heatwaves with gaps of 2 days or less are considered part of the same event.

    Why study MHWs?

    • MHWs are increasing in frequency due to climate change. MHWs increased by 54 per cent in the last 30 years.
    • MHW has severe socio-economic consequences such as fish mortality, and coral bleaching, and also has the potential to interact and modify other extreme events such as tropical cyclones.

    Way Forward

    • Marine heatwaves clearly have the potential to devastate marine ecosystems and cause economic losses in fisheries, aquaculture, and ecotourism industries.
    • However, their effects are often hidden from view under the waves until it is too late.
    • By raising general awareness of these phenomena, and by improving our scientific understanding of their physical properties and ecological impacts, we can better predict future conditions and protect vulnerable marine habitats and resources.

     

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  • Theri Desert in Tamil Nadu

    Most of us may not know the small desert situated in the state of Tamil Nadu. It consists of red sand dunes and is confined to the Thoothukudi district.

    Theri Desert

    • The red dunes are called theri in Tamil.
    • They consist of sediments dating back to the Quaternary Period and are made of marine deposits.
    • They have very low water and nutrient retention capacity.
    • The dunes are susceptible to aerodynamic lift.
    • This is the push that lets something move up. It is the force that is the opposite of weight.

    Mineral composition of Theris

    • The analysis of the red sand dunes reveal the presence of heavy and light minerals.
    • These include Ilmenite, Magnetit, Rutile, Garnet, Zircon, Diopside, Tourmaline, Hematite, Goethite, Kyanite, Quartz, Feldspar, Biotite.
    • The iron-rich heavy minerals like ilmenite, magnetite, garnet, hypersthene and rutile present in the soil had undergone leaching by surface water.
    • They were then oxidised because of the favourable semi-arid climatic conditions.

    How did they form?

    • Theris appear as gentle, undulating terrain.
    • The lithology of the area shows that the area might have been a paleo (ancient) coast in the past.
    • The presence of limestone in many places indicates marine transgression.
    • The present-day theris might have been formed by the confinement of beach sand locally, after regression of the sea.
    • When high velocity winds from the Western Ghats blew east, they induced migration of sand grains and accumulation of dunes.

    Another story of their formation

    • Another view is that these are geological formations that appeared in a period of a few hundred years.
    • The red sand is brought from the surface of a broad belt of red loam in the plains of the Nanguneri region (about 57 kilometres) by south west monsoon winds during May-September.
    • The winds after draining the moisture behind the Mahendragiri hill and the Aralvaimozhi gap of the Western Ghats become dry and strike the plains in the foothills, where vegetation is sparse.
    • Deforestation and the absence of vegetative cover in the Aralvaimozhi gap and the Nanguneri plains are considered to be the major causes of wind erosion.

     

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