The Rs 1,808-crore modernisation and expansion plan for Chennai airport, which was recently cleared by the Public Investment Board and expected to begin this September, may not be sufficient to cope with projected growth in passenger traffic.

Annual domestic and international capacity at the modernised airport, which will be done by the Airports Authority of India, is being raised from the current 9 million to 23 million by November 2010. But it is estimated that domestic capacity would be saturated in two years -- that is, by 2012.

The modernisation plan includes constructing an additional domestic terminal, which will increase annual capacity from 6 million currently to 16 million, an addition of 10 million. But this capacity will be enough to handle the growth in passenger traffic till 2012, when it will hit around 16 million.

The international terminal will also increase annual handling capacity from 3 million currently to 7 million. This capacity, however, will be enough to handle passengers till 2017-18, when the number of passengers will hit 10 million.

A proposal for a new airport in Sriperumbudur is also unlikely to ease matters. For one, if the approvals come through next year at the earliest, the airport will only be ready by 2014. This will leave a two-year period when passenger traffic will exceed capacity in the domestic terminal.

This rationale was given to the fministry when it asked how the construction of the second airport would impact the first.

"This could be a problem. But we still have the international terminal as a back-up. So if a second airport does not come up by then, we can shift some of the air traffic and airlines to the international terminal," said an AAI official working on a contingency plan.

The AAI has, however, asked the state government for additional 940 acres of land to build another parallel runway that would increase the saturation life of the airport by another 10 years.

It also said that given the land constraints, the terminal area would fail to match international standards or those set by the Delhi airport or the greenfield Hyderabad and Bangalore airports.

The overall unit area of the per peak hour passenger, which means the area one passenger gets at the terminal during peak hours, would come to 16.22 square metres (sq mt) against international standards of 25 sq mt.

On the international side, the numbers are 22.83 sq mt against a global norm of 30 sq mt.

The upgraded Delhi airport will provide peak-hour passengers 36 sq mt, Hyderabad 26 and Bangalore 35.21.

The upgraded Chennai airport will be the first in India to have a runway built over the Adyar a river.