A Rain and Cloud Physics Research (RCPR) Centre was set up in 1955 at the National Physical Laboratory, New Delhi for undertaking scientific studies on Cloud Physics and Rainmaking. The RCPR Centre conducted a long series of ground based salt seeding experiments in north India during the southwest monsoon seasons (June-Sept.) of 1957-1966. The results of these experiments showed on the average, an increase of about 20 percent in rainfall on seeded days