It's not unusual in cities across India to see giggling children chasing each other around piles of sand or playing with shovels as their mothers keep an eye on them from nearby.
But these scenes of childhood glee rarely take place in playgrounds.
Hundreds of thousands of children in India grow up on construction sites, living with parents for whom childcare and workplace safety are all but unknown.
"But one feels afraid. There are always cars passing by."
As Delhi installs new public transport systems, and shiny apartment blocks replace old one-storey homes, builders are hard at work -- with their small children playing around them.
The risk of injury is high and school attendance is low as the migrant workers, who often sleep on the building sites, have no idea where local schools are or just do not have the time to take their children there.
"We've heard of children falling and drowning on site," said Mridula Bajaj, who heads the Delhi branch of Mobile Creches, an organisation trying to improve conditions for labourers and their children.
The group estimates that some 400,000 children accompany their parents on work sites in the capital alone, and probably millions nationwide.
With hundreds of thousands of workers flocking to the city each year in search of work, and willing to live in abject conditions, it is a struggle to get employers to provide even basic services.
"We think we've made a beginning but, as soon as we turn our backs, we are back where we started," said Bajaj.
Mobile Creches estimates that it currently has daycare in place for no more than 2,000 children -- largely because of resistance from developers and lax government enforcement.
At the few work sites that do provide care, women workers say they are able to work better without worrying about their children.
At one site in Gurgaon, an affluent southern suburb that is home to multinational corporations and call centres, babies sleep in makeshift cribs as older children sing songs and read while their parents build luxury apartments.
"If the school was not here, I wouldn't be able to work. We would only have one person earning in the family," said brick carrier Vimla Pal, who has two children under the age of three.
"I would have to wait until my child was four or five to work."
The daycare centre teaches children to count and read, and helps prepare them for a proper school -- although many of them will never attend one.
Kranti, one of the children at the centre, used to study at school in her village in central Madhya Pradesh state before her parents migrated to Delhi.
"I have gone to school for three years in all," said Kranti, 10, who also attended school in Delhi until she dropped out because the site where her parents now work is too far away.
"There is no transport," she said.
The lack of services for children is just a small part of the problem, with most construction workers living in slum conditions in spite of a law passed more than a decade ago to remedy the problem.
On larger sites, employers are required by law to organise housing and toilets, while sites with more than 50 women are supposed to provide daycare.
But it doesn't often work out like that.
"It's so easy in India to break the rules," said Bajaj.
Scores of construction sites employ too few people for the rules to apply to them, but even large employers flout the regulations and the government itself is accused of being one of the worst offenders.
Several of the workers toiling on the bus corridor, a Delhi government project, said they had lived for months under a bridge opposite a five-star hotel in huts made of sticks covered by sheets of tarpaulin.
Their toilets were the nearest park.
"It costs 4,000 to 5,000 rupees to rent a room in Delhi," explained one worker on the project, asking not to be named. "So the company put us here."