The 150-year-old Madras University on Friday conferred Honorary Doctorates of Literature (D.Litt) on Prime Minister Manmohan Singh, Congress president Sonia Gandhi and Tamil Nadu Chief Minister M Karunanidhi at a special convocation to commemorate its sesquicentennial-year celebrations.

The doctorates were conferred on them by University Chancellor and Tamil Nadu Governor S S Barnala at a special convocation and valedictory function held at the University auditorium.

Reading out the citation, University Vice-Chancellor Prof S Ramachandran said the Prime Minister was being conferred the Doctorate in recognition of his service for economic progress of the country and commitment to secularism and democracy.

Sonia Gandhi was being honoured for her service to the people of all sections in the country upholding secular values and Karunanidhi for his service for flourishment of Tamil language, Dravidian movement and striving for social justice.

United Nations Industrial Development Organisation Director-General Kandeh K Yumkella was also conferred D.Litt in recognition of his services to eradicate poverty and practising people-centred management.

After receiving the doctorates, Sonia laid the foundation stone for the university's new campus at Guindy and an entrance arch at Chepauk. Karunanidhi laid the foundation stone for another new campus of the university at Taramani.