New Delhi: The finding of a recent study by a US think tank that Delhi, not Mumbai or Kolkata, is the largest metropolis in the country in terms of population may probably explain why the city’s infrastructure often seems inadequate.

According to O.P. Sharma, a co-author of the report published by Population Reference Bureau (PRB), and a former deputy director of India’s census operations, Delhi’s population has been underestimated by the government and this “adversely affects planning, policies, and the eventual development".

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PRB has arrived at its conclusion by using data from the population census of 1991 and 2001, and a different definition of the concept of an urban agglomeration than that used by the Indian census.

An urban agglomeration comprises one or more towns, and parts of villages contiguous to the town or towns. In Delhi’s case, parts of Haryana, including Gurgaon and Faridabad, and Uttar Pradesh, including Ghaziabad and Noida, would have to be included in the larger definition of the Delhi urban agglomeration.

While India recognizes the concept of an urban agglomeration, current norms governing population census say that “state boundaries" cannot be crossed, said Sharma.

“This rule has no effect upon the population size of the Kolkata urban agglomeration and the Greater Mumbai urban agglomeration, which are located far from their state borders. But it does affect Delhi," he added.

“If we apply the globally accepted definition of an urban agglomeration, then Delhi is, as of now, India’s biggest city," said Sharma.

According to the 2001 census, the Delhi urban agglomeration had a population of 12.9 million, the Greater Mumbai urban agglomeration, 16.4 million, and the Kolkata urban agglomeration, 13.2 million.

Sharma said that if these numbers were recalculated on the basis of the other definition of urban agglomeration, Delhi’s population in 2001 would have been 16.2 million.

And, assuming that the growth in population since 2001 has happened at the same rate at which it happened every year between 1991 and 2001, the Capital’s population today would be higher than Mumbai’s.

“In 2007, the ‘redefined’ Delhi urban agglomeration has (a population of) 21.5 million people against 19.3 million in Greater Mumbai," he said.

Sharma added that Delhi’s problem was unique because it shared boundaries with two states, Uttar Pradesh and Haryana. Apart from Bangalore, which shares a boundary with Tamil Nadu, almost no other Indian state capital abuts other states.

At least part of the urban population in Faridabad, Gurgaon, Ghaziabad and Noida consume Delhi’s resources, including roads, power, water and parking on a daily basis. Sharma’s contention is that the insular definition of the Delhi urban agglomeration prevents planners from accounting for this.

However, the National Capital Region (NCR) Planning Board, created in 1985 to prepare and coordinate regional plans within NCR, refutes his. The board was set up to plan for the larger area of Delhi and its environs—including those that are in Haryana, Uttar Pradesh and Rajasthan.

“We go by census figures. But our planning (to understand the pressure on Delhi’s resources) is not inadequate. While planning, we take care of the population coming in from the neighbouring towns," said J.N. Barman, joint director (regional planning), NCR Planning Board.

India’s former urban development secretary Anil Baijal, currently an adviser to infrastructure finance firm IDFC Ltd, said that population estimates in the past have “consistently been awry", and that there is a need to look beyond the numbers.

“The truth is every (city’s) master plan has somewhat underestimated projected population for the period they (the master plans) were valid for. And even to the extent that they were correct, we haven’t provided resources, mostly because of a lack of resources or the affordability...," he added.

Rahul Chandran contributed to this story.