"In a country where Rani Laxmi Bai is hailed, there is the practice of female foeticide. There is no bigger sin," he said at a function in Banaras Hindu University here as part of 'Good Governance Day' celebrations.
Modi, who was talking in the context of his 'Beti-bachao' programme, asked whether a message could be spread for stopping this practice.
He also suggested holding of 'kavi sammelans' on the social evil along with spreading the message about cleanliness.
"Please work for the nation...Dreams can be fulfilled," he said.
The Prime Minister also expressed concern over the problem of malnutrition of women and children in a country where there is a tradition of feeding even "ants and cows".