geography

Arctic Region and Arctic Council

The Arctic is a polar region located at the northernmost part of Earth.

8 Jul, 2020

BRAHMAPUTRA AND ITS TRIBUTARIES

About Brahmaputra River: The Brahmaputra called Yarlung

3 Jul, 2020
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    Current Affairs – 21st September 2021

    1.     PURNIMA

    • News: Devotees take a holy dip in the Ganga on the occasion of ‘Purnima’ and ‘Pitra Paksha’ in Prayagraj.
    • About Purnima:
      • Pūrṇimā is the word for full moon in Sanskrit.
      • The day of Purnima is the day (Tithi) in each month when the full moon occurs, and marks the division in each month between the two lunar fortnights (paksha), and the Moon is aligned exactly in a straight line, called a syzygy, with the Sun and Earth.
      • Full moon is considered the third of the four primary phases of the Moon; the other three phases are new moon, first quarter moon, and third quarter moon.
      • The full moon shows 100% illumination, causes high tides, and can concur with lunar eclipses.
    • About Sidereal and Synodic Month:
      • The sidereal month is the time the Moon takes to complete one full revolution around the Earth with respect to the background stars.
      • However, because the Earth is constantly moving along its orbit about the Sun, the Moon must travel slightly more than 360° to get from one new moon to the next. Thus, the synodic month, or lunar month, is longer than the sidereal month.
      • A sidereal month lasts 27.322 days, while a synodic month lasts 29.531 days.
    • About Tides:
      • Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun, and the rotation of the Earth.
      • The predictions are influenced by many factors including the alignment of the Sun and Moon, the phase and amplitude of the tide (pattern of tides in the deep ocean), the amphidromic systems of the oceans, and the shape of the coastline and near-shore bathymetry.
      • They are however only predictions, the actual time and height of the tide is affected by wind and atmospheric pressure. Many shorelines experience semi-diurnal tides—two nearly equal high and low tides each day. Other locations have a diurnal tide—one high and low tide each day.
      • A “mixed tide”—two uneven magnitude tides a day—is a third regular category.
      • Tides vary on timescales ranging from hours to years due to a number of factors, which determine the lunitidal interval. To make accurate records, tide gauges at fixed stations measure water level over time. Gauges ignore variations caused by waves with periods shorter than minutes.
      • These data are compared to the reference (or datum) level usually called mean sea level.
      • Tidal phenomena are not limited to the oceans, but can occur in other systems whenever a gravitational field that varies in time and space is present. For example, the shape of the solid part of the Earth is affected slightly by Earth tide, though this is not as easily seen as the water tidal movements.

    2.     SMOG

    • News: The Delhi government has finished installation of filters in the smog tower in Connaught Place, which was inaugurated last month. Also, a team from IIT Bombay has started a study on the impact of the tower on the air quality, officials said.
    • About Smog:
      • Smog is a kind of air pollution, originally named for the mixture of smoke and fog in the air.
      • Smog, or smoke fog, is a type of intense air pollution.
      • The word “smog” was coined in the early 20th century, and is a contraction (portmanteau) of the words smoke and fog to refer to smoky fog due to its opacity, and odor.
      • The word was then intended to refer to what was sometimes known as pea soup fog, a familiar and serious problem in London from the 19th century to the mid-20th century.
      • This kind of visible air pollution is composed of nitrogen oxides, sulfur oxide, ozone, smoke and other particulates.
      • Man-made smog is derived from coal combustion emissions, vehicular emissions, industrial emissions, forest and agricultural fires and photochemical reactions of these emissions.
      • Smog is often categorized as being either summer smog or winter smog. Summer smog is primarily associated with the photochemical formation of ozone.
      • During the summer season when the temperatures are warmer and there is more sunlight present, photochemical smog is the dominant type of smog formation.
      • During the winter months when the temperatures are colder, and atmospheric inversions are common, there is an increase in coal and other fossil fuel usage to heat homes and buildings.
      • These combustion emissions, together with the lack of pollutant dispersion under inversions, characterize winter smog formation. While photochemical smog is the main smog formation mechanism during summer months, winter smog episodes are still common.
      • Smog formation in general relies on both primary and secondary pollutants.
      • Primary pollutants are emitted directly from a source, such as emissions of sulfur dioxide from coal combustion.
      • Secondary pollutants, such as ozone, are formed when primary pollutants undergo chemical reactions in the atmosphere.

    3.     BIO – DECOMPOSER

    • News: The Delhi government will start spraying bio-decomposer for free in 4,000 acres of paddy fields in Delhi from October 5, to tackle stubble burning, Environment Minister Gopal Rai.
    • About Bio – Decomposer:
      • Bio-decomposer is a solution, which, if sprayed in fields, decomposes straw and stubble into manure. The government sees it as a solution to stubble burning and has also been urging other States to adopt it.
      • A bio-decomposer capsule, developed by Pusa Institute, is made into a solution through a week-long process and then sprayed on stubble and straw left behind on fields after harvesting. The Delhi government first sprayed it last year and it claimed that the results were positive.

    4.     NILGIRI BIOSPHERE RESERVE

    • News: A lone wild elephant entered human habitats near Meenangadi in Wayanad district on Monday, triggering panic among people.
    • About Nilgiri Biosphere Reserve:
      • The Nilgiri Biosphere Reserve is an International Biosphere Reserve in the Western Ghats and Nilgiri Hills ranges of South India.
      • The Nilgiri Sub-Cluster is a part of the Western Ghats, which was declared a World Heritage Site by UNESCO in 2012.
      • It is the largest protected forest area in India, spreading across Tamil Nadu, Karnataka and Kerala.
      • It includes the Aralam, Mudumalai, Mukurthi, Nagarhole, Bandipur and Silent Valley national parks, as well as the Wayanad, Karimpuzha, and Sathyamangalam wildlife sanctuaries.
      • Nilgiris Biosphere Reserve is India’s first and foremost biosphere reserves with a heritage, rich in flora and fauna. Tribal groups like the Badagas, Todas, Kotas, Irullas, Kurumbas, Paniyas, Adiyans, Edanadan Chettis, Allar, Malayan, etc., are native to the reserve.
      • India’s natural Gold fields are also located in the regions in and around Nilgiris Biosphere Reserve scattered in the states of Karnataka, Kerala, and Tamil Nadu.
      • The reserve encompasses 5,520 km² in the states of Tamil Nadu (2537.6 km²), Karnataka (1527.4 km²) and Kerala (1455.4 km²).
      • It forms an almost complete ring around the Nilgiri Plateau.
      • The biosphere lies between 10°50′N and 12°16′N latitude and 76°00′E to 77°15′E longitude.
      • Rainfall ranges from 500mm to 7000mm per year.

    5.     GST RATES

    • News: The GST Council may have put off a proposal to tax coconut oil sold in pack sizes below one litre at 18% instead of 5% levied on edible oils, but analysts are puzzled by the idea since similar moves in the pre-GST tax regime had been challenged successfully in court.
    • Details:
      • The Council’s Fitment Committee had recommended that coconut oil, packed and sold in containers of less than one litre should be classified as hair oil, and taxed at the 18% rate levied on personal care items, while the 5% GST could continue for the same oil when sold in containers of one litre or more.