Prime Minister Narendra Modi on Tuesday invoked Sant Ravidas, a mystic poet of the Bhakti Movement, on his birth anniversary to urge people to end caste discrimination and identify those who promote it for "self interest". Modi, who was in Varanasi to launch several development projects, said that caste discrimination is an impediment in achieving social harmony. Earlier, PM Modi inaugurated Madan Mohan Malviya Cancer Centre of the Banaras Hindu University and flagged off the first electric locomotive converted from a diesel engine in the country at Diesel Locomotives Works (DLW). He also laid the foundation stone of Ravidas Janmasthali (birthplace) area development project. The Prime Minister's visit comes just a few weeks ahead of the Lok Sabha polls.