The famous 17th-century mausoleum, built by the Mughal Emperor Shah Jehan for his favourite wife, Mumtaz, was shrouded in acrid smog, as it often is.
Harper is on a trade mission to India with the aim of tripling trade with India by 2015.
He pronounced himself impressed by the Taj, which he did manage to see close up, although the traditional photo-op location, at some distance from the monument, made it harder to see.
Asked if he was planning a similar monument for his own wife, Harper said, "my wife's tastes are a bit more modest."
Business deals in New Delhi
Later Monday, Harper attended a business roundtable in New Delhi, intended to showcase 14 trade and investment agreements that "demonstrate the increasing depth of the Canada-India relationship," according to a Canadian government news release.
International Trade Minister Ed Fast emerged from the meeting to say that $2.5 billion in new business deals with India are now in the works. Some of that, he conceded, is in the form of memoranda of understanding – not cash in the bank.
The largest deal was a previously announced $1.2-billion agreement between Montreal's La Coop fédérée and Indian Farmers Fertilizer Cooperative (IFFCO) to build a urea production plant (used for nitrogen fertilizer) in Bécancour, Que., creating 200 local jobs.
Another technology research deal between Prairie Pulp & Paper Inc. of Winnipeg and Central Pulp & Paper Inc. from Saharanpur, India, will see a new wheat straw-based pulp and paper plant built in Manitoba, representing a $500-million to $600-million investment.
Montreal's Bombardier was also highlighting two deals: a new $200-million contract from Mumbai Railway Vikas Corporation to design and manufacture equipment for 72 commuter trains with 12 cars each operating on the Mumbai suburban rail network, on top of another deal with the Delhi Metro Rail Corporation for 614 cars, worth over $900 million.
Fast referred to the business environment in India as "opaque" and "byzantine."
He added that a foreign investment protection agreement, which is one of the government's main goals, is still not ready to sign, even after eight years of negotiation.
The two nations have yet to agree on the strings attached to Canada selling India uranium under a 2-year-old nuclear deal.
Singh government under pressure
Stewart Beck, Canada's high commissioner to India, has identified four main areas for potential trade growth: food security, educational services, oil and gas, and infrastructure support.
But part of the reason the other agreements have been hard to reach, Beck said, is that India is coping with its own internal issues.
The country faces a controversy over how it has handled the taxation of British-owned Vodafone, and a scandal over the handing out of coal mining permits. The government of Manmohan Singh is also in a minority situation, and has not been able to move forward as quickly with economic reforms.
And Canada too has had his share of controversy in the area of foreign investment, with its recent temporary blocking of Malaysian company Petronas' bid for gas producer Progress Energy Resources, and its drawn out review of Chinese company CNOOC's takeover of energy firm Nexen Inc.
On the nuclear front, Canada has insisted on administrative conditions that would allow it to track exactly where the uranium sold to India ends up. India has balked at that.
Canadian vehicles travel with PM
Another unrelated issue that has emerged on Harper's trip is his use of vehicles shipped from Canada to India, in the style of a U.S. president.
Reporters noticed that, in Agra, the prime minister was driven around in a black SUV with Ontario plates. A second Canadian car met him on arrival in New Delhi.
The PMO referred queries about the rationale for these vehicles to the RCMP, which issued a statement Monday morning saying the deployment of resources is dictated by "operational requirements, including public and officer safety considerations, and a threat assessment of the events/environments."
"The RCMP evaluates these things and they make the operational decisions," the prime minister's spokesman Andrew MacDougall told reporters on the tour.
"I don't have the costs in front of me. We won't know that for a while," he said, saying the full price of the security measure will be disclosed when it's available.