NEW DELHI: Singapore Airlines' and Tata Sons' choice of Delhi as the operations base for their new airline is yet another sign that the political capital has overtaken Mumbai as the country's aviation hub.

SIA and Tata Sons announced last month that their joint venture – Tata SIA Airlines Limited – would take off from New Delhi, with an initial investment of US$100 million.

Just six months earlier, Air India, the government-run national carrier, moved its headquarters to Delhi after five decades in the iconic Air India Building, a 23-storey commercial tower in the heart of Mumbai.

For years the sleepy government capital to Mumbai's throbbing metropolis, Delhi is now the undisputed aviation centre of India, thanks to a spacious Terminal 3 that opened in 2010, and an abundance of land to expand.

Mumbai, by contrast, is still operating one runway, hemmed in by slum dwellers in a city where space is a luxury.

Its new Terminal 2 is scheduled to open by the end of the year but may not help it regain its No.1 spot any time soon.

With Indian low-cost carriers Spicejet, started in 2005, and Indigo, started in 2006, also based out of Delhi, the capital's Indira Gandhi International Airport overtook Mumbai's Chhatrapati Shivaji International Airport in terms of the passenger numbers in 2011.

For the year to March this year, Mumbai handled 30.21 million passengers, while Delhi handled 34.37 million.

Mumbai, however, handled more cargo – 635,163 tonnes to Delhi's 546,311 tonnes.

It is still early days for the Indian aviation industry. Only 160 million of the 1.2 billion population fly annually.

According to some estimates, that is set to triple in the next 12 years. That is why building infrastructure is so important.

Prime Minister Dr Manmohan Singh has approved the upgrading of airports across the country including in northeast India, where the airports in Agartala and Imphal will be upgraded to international status to improve trade and tourism.

Singh also announced a plan for building 100 smaller airports over 10 years.

As the industry matures, India should end up with multiple aviation hubs like in the United States, instead of just one city, said Jitendra Bhargava, a former executive director of state-owned Air India.

But, for now, it appears that Delhi is king. It now has direct air links to 53 Indian cities, while Mumbai is connected to 42.

"The huge jump has come because of infrastructure growth, "I, Prabhakara Rao, chief executive of Delhi International Airport, told The Straits Times.

For decades, the two main national carriers – Air India and Jet Airways – were based in Mumbai.

In 2006, the government, as part of the privatisation drive, handed over the Delhi and Mumbai airports to two private companies, GMR Infrastructure and GVK Group, respectively.

But while Delhi quickly added a new terminal, Mumbai's expansion was delayed by a large slum that encroached onto airport land.

"Right now, there is no plane parking space available in Mumbai," said Rajan Mehra, former India head of Qatar Airways and India head of US-based Universal Weather and Aviation, a private jet operator.

"Mumbai will take a couple of years to catch up," he added.

In August, Air India started having B-787 Dreamliners fly non-stop from Delhi to Sydney and Melbourne, and is planning to fly to Rome and Milan this month.

But the airline has not written Mumbai off.

"Mumbai is always a main city for us," said an Air India spokesperson.

"Let's see what new infrastructure will come in and then management will look."

– By arrangement with the ANN/The Straits Times –