India wishes to build or to redesign 109 "smart cities" in a huge country where urbanisation is rapid and nightmarish.

Half of the most-polluted cities in the world are Indian and a third of the urban population does not have access to tap water. In Delhi, only 17 per cent of households are connected to the sanitation system.

In other words, the "smart cities" initiative launched by the Indian government in 2015 is extremely ambitious.

Its aim is to promote cities equipped with basic infrastructure providing all citizens with a decent quality of life, a clean environment and the use of smart solutions.

The government is committed to contributing a total of €6.9 billion (S$10.7 billion) to the projects selected, but has been careful not to give a precise definition of "smart solutions".

The municipal authorities are better placed to decide, having been told that each town "must set out its own project, its own vision and its proposal for a smart city, in keeping with the local context, its resources and its ambitions".

For example, the city of Agra, which is home to the Taj Mahal, wishes to construct a museum devoted to Moghul history to provide support for its tourism industry.

In Jaipur, located on the edge of the desert, the town-planning scheme focuses on the construction of green buildings, which save energy and harvest rainwater.

In India, there is no standard model of a smart city. The projects are selected in the context of a nationwide competition based on the "cooperative and competitive federalism" model promoted by Indian Prime Minister Narendra Modi.

Each municipality must present a project for the renovation, reconstruction or creation of a district while at the same time propose the setting up of at least one "smart" solution for the town as a whole, such as a traffic management system or the recycling of waste water.

Sixty of the 109 towns supported by the project have been chosen.

In matters of urban planning in India, being "smart" means designing cities which consume a minimum of environmental resources.

The number of city dwellers could increase by 500 million between now and 2050, which means India will have to build two cities each the size of Singapore each year.

Several mega-cities, such as Bangalore and Chennai, are already threatened by the exhaustion of their water tables. Many of their inhabitants get their water from cistern-trucks which take water from neighbouring rural areas.

In contrast to the model of the energy-consuming mega-cities, what if the smart 21st century city was "natural"?

Well-known Indian architect and city planner Romi Khosla has made an appeal for the creation of thousands of autonomous "natural cities, home to a multiplicity of local cultures, each with its own identity and unique way of functioning, which would protect them from the homogenisation of globalisation and climate change".

These towns, small in size, would be an alternative to mega-cities, in response to the challenges of urbanisation. It was Mahatma Gandhi who once said India "exists in its villages".

Whatever the path it takes, India will not escape the imperative of planning. Roads now are often planned and built after the foundations of buildings have been laid.

City planners often come after the real estate developers. But optimists predict that planning will one day replace anarchic development.