Cameron visits Kolkata landmarks, lauds city for great brains

"I think there are big opportunities. Your city is expanding. There is a huge need for infrastructure and for city planning, something that Britain has expertise in. Enormous amount of work is going on.

"You are thinking about how to clean up rivers and waterways. We had to do it in Britain about river Thames and others," Cameron said while interacting with students at the Indian Institute of Management-Calcutta.