If it's been said once, it's been said a thousand times -- India has a severe infrastructure deficit. From its rudimentary airports to its overcrowded trains, the need is evident everywhere and, unless things change, and change fast, all those new Tata Nanos taking to the road are only going to make matters worse.

"Nothing is more embarrassing than India's infrastructure," says Rajeev Malik, Macquarie's head of India and Asean (Association of Southeast Asian Nations) economics, at the bank's annual Asia-Pacific Infrastructure and Transportation conference in Hong Kong this week.

India's Planning Commission, the government body responsible for the country's five-year plans, projected a need for $520 billion in infrastructure investment through 2012. An estimated one-third, or around $170 billion, of that is supposed to come from the private sector.

Ask nearly any private sector infrastructure practitioner at Macquarie's conference and they say Indian infrastructure is on the up-and-up. "A large number of infrastructure funds have been set up and a lot more private equity funds are looking at Indian infrastructure in a serious fashion," says Amrit Pandurangi, leader of PricewaterhouseCoopers (PwC) infrastructure practice in India.

Yet, according to Pandurangi's own estimates, only $955 million was invested by institutional investors in Indian infrastructure last year -- the highest amount ever -- and Srei Infrastructure Finance's joint managing director Saud Siddique estimates that only $300 billion to $400 billion of the Planning Commission's estimates will be realised.

This outlook varies little from that expressed at the same Macquarie conference two years ago when practitioners were equally upbeat but said the sheer enormity of India's need made investment difficult.

Some positive developments have occurred in the intervening years. While Siddique estimates infrastructure investment will be significantly lower than the need expressed by the Planning Commission, it is still up significantly from the level invested during the previous five-year plan. The Congress party's re-election by a surprisingly large margin earlier this year has buoyed expectations of changes at the top and PwC's Pandurangi says public-private partnerships (PPPs) are now the government's "default" method for infrastructure finance.

Funds and financial institutions are also showing increased interest in India. "When funds look at markets in Asia, India is one of the few markets where they want to invest," says Michael Barrow, director of the infrastructure finance division at the Asian Development Bank.

Earlier this year, India's UTI Asset Management Company, HSH Nordbank and Kuwait's Noor Financial Investment Company launched the $500 million India Infrastructure Development Fund and joint chief executive of the Standard Chartered IL&FS Infrastructure Growth Fund, Andrew Yee, said in May that the fund plans to increase investment in Asian infrastructure, including India.

But no matter how many new private equity funds are set up or how many government bodies say infrastructure needs to be built, India's glacial pace of change will continue to hinder the country. It needed these billions of dollars in investment 10 years ago, not in the five or 10 years it will take for the projects on today's drawing boards to become a reality.