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Acid Rain in India: 34-Year IMD-IITM Study Finds Falling Rain pH

12 April 20251 min read
ENVIRONMENT & ECOLOGYAcid Rain in India:34-Year IMD-IITMStudy FindsFalling Rain pH12 April 2025safalsetu.com

Why in the news

A 34-year IMD and IITM study found air pollution making rain more acidic in several Indian cities.

Key facts

  • Rainwater chemistry tracked at 10 Global Atmosphere Watch stations, such as Visakhapatnam, Prayagraj, Srinagar, Pune and Port Blair.
  • Rain under pH 5.65 is acidic; pH has dropped steadily, mainly in urban-industrial zones.
  • Visakhapatnam: refineries, power plants, fertiliser units and shipping yards; Prayagraj and Mohanbari also fell.
  • Calcium particles, natural neutralisers, are falling in Prayagraj, Jodhpur and Nagpur; rising ammonium does not compensate.

Causes and contrast

  • Nitrates from vehicles, industry, crop-residue burning and household sources are increasing.
  • Jodhpur and Srinagar see milder acidity as natural dust, such as Thar Desert dust, neutralises acid.

Concerns

Weakening buffering threatens ecosystems, agriculture and health.

Exam angle

  • Agencies: IMD, IITM.

Test yourself

1. Below which pH value is rainfall classed as acidic in the IMD-IITM acid rain study?

The study treats pH under 5.65 as acidic rain.

2. Which agencies conducted the 1987-2021 acid rain study across 10 Global Atmosphere Watch stations?

IMD and Indian Institute of Tropical Meteorology carried it out.

3. Which pollutant group is the main contributor to acid rain, as per the IMD-IITM study notes?

Nitrate compounds are the main contributor and are increasing.

This topic is part of Daily Current Affairs 12 April 2025 (27 topics).

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