Public service announcements (PSAs) provide valuable information to the public to positively impact their lives without selling a product. This document discusses PSAs as an informal knowledge system in society. It outlines the objectives of studying PSAs, including how they communicate messages and their effects on social and economic growth. Case studies on India's "Pulse Polio" immunization campaign and the "Incredible India" tourism campaign are examined to show how PSAs can effectively change public opinion and behavior at the regional, national, and international levels through the use of emotional appeals.