current affairs - 2023-10-29

IITM Pune demonstrates cloud seeding can produce rainfall


A cloud seeding experiment conducted in Solapur, which is located on the leeward side of the Western Ghats and thus receives low rainfall — 384 mm and 422 mm of total rainfall from June to September 2018 and 2019, respectively — was able to achieve an 18% relative increase in rainfall or approximately 8.67mm more rainfall. 

What is the cloud seeding?

  • Cloud seeding is a weather modification technique used to alter the amount and kind of precipitation that falls from clouds. It’s sometimes referred to as ice-nuclei seeding. 
  • Cloud seeding involves planes spraying chemicals into clouds to condense tiny particles into larger raindrops. Among the compounds utilized are: 
    • Dry ice
    • Silver iodide aerosols

What are the uses of the Cloud Seeding?

  • Drought Mitigation: Cloud seeding can be used to mitigate the impacts of drought by boosting precipitation in water-stressed areas. This is especially useful in agricultural regions that rely on regular rainfall for crop growth, as well as in areas with limited water resources.
  • Water Resource Management: Cloud seeding is used in water resource management to supplement water supplies in reservoirs, lakes, and aquifers. Increased precipitation can help replenish these water sources, offering a more stable water supply for a variety of applications such as municipal water use and industrial processes.
  • Snowpack Augmentation: Cloud seeding can be used to boost snowfall in areas with ski resorts or where snowmelt is vital for water supply. This is especially crucial for preserving water resources in locations where snowfall is a significant source of freshwater during the spring and summer.
  • Hail Suppression: In severe thunderstorms, cloud seeding can be employed to lessen the size and severity of hailstones. Certain compounds can be introduced into storm clouds to induce the creation of smaller hailstones, which can assist in preventing damage to crops, property, and cars.
  • Air Quality Improvement: Cloud seeding is in some circumstances a method of dispersing and reducing air pollution. Cloud seeding can help remove pollutants and particle debris from the atmosphere by boosting precipitation.

What was the study done at IIT Pune based on?

Based on the “Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX) phase-4,” the study at the Indian Institute of Tropical Meteorology (IITM) in Pune, India, aimed to investigate the efficacy of cloud seeding in deep convective clouds and develop a cloud seeding protocol. 

  • Objective: The major goal of the study was to determine the effectiveness of cloud seeding in increasing rainfall.
  • Location: The study was carried out in Solapur, which receives minimal rainfall due to its location on the leeward side of the Western Ghats.
  • Period: The studies were conducted throughout the summer monsoon seasons in 2018 and 2019.
  • Methods: Two aeroplanes were utilized in the study to test various cloud properties and to seed clouds with calcium chloride flares.
  • Randomized Seeding Experiment: A randomized experiment was carried out, in which convective clouds were selected based on particular criteria, with some clouds seeded and others left unseeded.
  • Cloud Selection Criteria: Clouds were chosen based on factors such as liquid water content, vertical motion in the cloud, and the ability of a convective cloud to produce rainfall by cloud seeding.
  • Rainfall Enhancement: The study found an 18% relative increase in rainfall, resulting in roughly 8.67 mm of additional rainfall two hours after seeding.

What are the benefits for India with the successful testing of cloud seeding?

  • Increased Water Resources: Cloud seeding can assist in enhancing rainfall in water-stressed areas. This means that additional water resources are available for a variety of uses, such as drinking water, agriculture, and industrial use.
  • Agricultural Advantages: Increased rainfall from cloud seeding can boost agricultural production. Ample rainfall is required for crop growth, and cloud seeding can help increase crop yields.
  • Drought Mitigation: Cloud seeding can be an effective strategy for reducing the impacts of drought. It has the potential to replenish water supplies, alleviate water shortages, and lessen the impact of prolonged dry spells on both rural and urban regions.
  • Water Supply: Cloud seeding can supplement water supplies in reservoirs, lakes, and aquifers, providing municipalities and industry with a more reliable source of freshwater.
  • Improved Air Quality: Cloud seeding can assist in reducing air pollution by removing pollutants and particulates from the atmosphere in some instances. This can result in improved air quality and public health advantages.
  • Reduced Hail Damage: In severe thunderstorms, cloud seeding can be employed to minimize the size and intensity of hailstones. This can assist in preventing hail damage to crops, property, and vehicles.


The results of the experiment imply that, given the right conditions, cloud seeding can be an effective approach for increasing rainfall in select places. While it is not a stand-alone option for drought mitigation, it can help to increase water availability in water-stressed places like Solapur.