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📌 The Question:
Artificial way of causing rainfall to reduce air pollution makes use of

(a) silver iodide and potassium iodide
(b) silver nitrate and potassium iodide
(c) silver iodide and potassium nitrate
(d) silver nitrate and potassium chloride

✅ Correct Answer: (a)

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🔍 Classroom Explanation:

Artificial rain, commonly known as cloud seeding, is a weather modification technique used to enhance precipitation and sometimes to reduce air pollution by washing out suspended particulate matter (PM) from the atmosphere.

• Silver iodide (AgI) has a crystalline structure similar to ice, making it an effective ice-nucleating agent.
• Potassium iodide (KI) can also act as a cloud condensation nucleus, helping water droplets coalesce and fall as rain.

These substances are dispersed into suitable clouds using aircraft or ground-based generators, encouraging rainfall that can flush pollutants from the air.

👉 Therefore, option (a) is correct.

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🧠 Curiosity Raiser:
Did you know? Cloud seeding has been used in cities like Beijing and Delhi during severe air pollution episodes to temporarily improve air quality.

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📚 Enrich Notes (Prelims Edge):

• Cloud seeding works only when clouds with sufficient moisture already exist
• Used for:
  • Rain enhancement
  • Hail suppression
  • Fog dispersal
  • Air pollution mitigation (short-term)
• India has experimented with cloud seeding under projects in Karnataka, Maharashtra, and Delhi NCR

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🕊️ IAS Monk Whisper:
“We cannot command the clouds, but we can gently persuade them.”