Physical Geography
Fujiwhara Effect
- Two potential cyclonic storms are forming in the Bay of Bengal, with global forecast models indicating a possible Fujiwhara interaction between them.
About Fujiwhara Effect:
- It is a rare meteorological phenomenon where two nearby cyclonic systems begin to rotate around a common centre due to interaction of their wind circulations.
- Identified by Sakuhei Fujiwhara (1921), it occurs mostly in the tropical cyclone belt when storms are within ~1,400 km of each other.
Conditions necessary for the effect to occur:
- Two tropical cyclones formed around the same time in the same ocean region.
- The distance between the centres (or eyes) of the cyclones is less than 1,400 km.
- An intensity that could vary between a depression (wind speed under 63 km/hour) and a super typhoon (wind speed over 209 km/hour).
Hayli Gubbi Volcano
- A massive volcanic ash cloud from Ethiopia’s Hayli Gubbi volcano—which erupted after nearly 10,000 years—has drifted toward India, raising concerns over air quality and aviation.
- Hayli Gubbi is a shield volcano in Ethiopia’s Afar Region, known for broad, gently sloping volcanic structures formed by low-viscosity basaltic lava typical of the East African Rift system.
Impact on India:
- Air Quality:
- Ash is at high altitudes, limiting ground-level mixing; Delhi is unlikely to see major AQI deterioration.
- Skies may appear hazy/darker but pollutants will remain mostly aloft.
- Health & Climate:
- SO₂ can contribute to acid rain regionally, but concentrations over India appear limited.
- Volcanic particles may briefly affect solar radiation and visibility.
Environment and ecology
Centre for Research on Energy and Clean Air (CREA)’s Study Report
- A new analysis shows that 60% of India’s districts (447 out of 749) experience year-round exposure to unhealthy levels of PM2.5 air pollution, not just in winter.
- None of the districts met the WHO air quality guideline of 5 µg/m³ for PM2.5.
- India’s own limit is 40 µg/m³, which is eight times higher.
- Most polluted regions: Delhi (11 districts) and Assam (11 districts) together account for almost half of the top 50 most polluted districts.
- Cleaner regions: Majority of districts in Andhra Pradesh, Telangana, Kerala, Sikkim, Goa, Karnataka, and Tamil Nadu fall within national safety limits.
- This highlights a clear pollution divide: northern and eastern States are hotspots, while southern and coastal regions remain relatively cleaner.
Seasonal patterns:
- Winter (Dec–Feb): 82% of districts (616 of 749) exceed national standards due to increased emissions and stagnant weather.
- Monsoon (June–Sept): 90% of districts (675 of 749) show pollution levels within safe limits due to rain and atmospheric cleansing.
