This information has been made public by the PMO as part of obligations under the mandatory proactive disclosure clause of the Right to Information Act.
The information reveals that Singh undertook 67 travels since 2004 when he took over as PM, of which bills of five have not been received. The bills received from the rest 62 visits show that Rs 642.45 crore was spent on air travel.
"We have been noticing a lot of public interest in the visit of such high dignitaries as the President, the Vice President and the Prime Minister of India. Quite often, one comes across RTI applications seeking similar information about these visits," Chief Information Commissioner (CIC) Satyananda Mishra had said.
Last year, the information accessed by PTI had revealed that former President Pratibha Patil had spent Rs 223 crore on her visits abroad during her five years which triggered a debate on expenditure over VIP visits.
This was followed by Rs 22.70 crore spent on air travel to Washington DC, USA and Brazil in 2010 where he had gone to attend the Nuclear Security Summit, BRIC Summit and IBSA Summit.