PM Narendra Modi, Kerala Governor P Sathasivam, CM Pinarayi Vijayan and Union Minister Venkaiah Naidu take a ride on the newly launched Kochi metro in Kerala on Saturday. Pic/PTI

PM Narendra Modi on Saturday called for a reading and library movement across the country that would not just make people literate but bring about social and economic change. He urged people to "give a book instead of a bouquet as a greeting", saying there is no joy greater than reading and no strength greater than knowledge.