"It is very challenging to teach in IIT. Some undergraduate students are smarter than the professors," Rao, who had earlier taught at the IIT, said.
The 'Bharat Ratna' awardee was addressing students and teachers at the 60th convocation of IIT, Kharagpur.
Describing IITs as a wonderful garden, he said all kinds of trees, fruits and flowers could be found in the multi-faceted atmosphere of the institute.
He urged students to always think about what they can contribute to the country.