New Delhi: In his Mann Ki Baat address, Prime Minister Narendra Modi cautioned people against following superstitious beliefs, saying they prevent one from seeing the truth."Let us discuss a subject that is thousands of years old - one that has been deeply ingrained in human society for millennia. That subject is superstition. Superstition is often not merely a misconception; it begets fear, and when fear dominates the mind, a person stops seeing the truth. People steeped in superstition begin making decisions without logic or knowledge of the facts - decisions that lead to great harm," Modi said.The PM expressed satisfaction that there are several people who dispel and challenge such superstition on the basis of science, experience and logic.Modi shared the prevalence of one such superstitious belief in Assam about the Hargila bird. This rare species which plays a key role in keeping nature clean was considered inauspicious, their sight disliked and the trees housing them cut. A campaign by biologist Purnima Devi Barman about the environmental benefits due to these birds changed the mindset of locals.