It's 7 AM and the alarm is going off and your body thinks it's still the middle of the night.

Everyone gives the same advice: sleep earlier. But what if the problem isn't you?

India is about 29 degrees longitude wide. 

That's nearly two hours of solar time between its eastern and western ends.
Yet the whole country runs on one clock, as it has since the mid-1950s.

Now picture a school in each city, both with an 8 AM bell. Is it the same morning for both children?

I wanted to know what that difference does to a child's sleep.

An economist, Maulik Jagnani, asked a similar question in a paper called Children's Sleep and Human Capital Production. 

It was published in the Review of Economics and Statistics in 2024.

He used India's 1998–99 Time Use Survey, which has nearly 14,000 weekday diary entries from children aged 6 to 16 across six states. He matched their daily routines with the sunset time in their district.

So when the sun set an hour later, children went to bed about 22 minutes later. 

They went to bed later but still woke up at the same time.
The school decided that.

The result was about 28 minutes less sleep a night.

Would you notice 28 minutes? Most parents wouldn't.

They studied about 40 minutes less. They napped more. And they spent more than an hour extra on indoor leisure.

One obvious objection: a later sunset means more daylight to study by, which matters where power cuts are common. 

Jagnani tested alternative explanations, including whether other factors related to daylight could explain the results. Despite the later sunset, children spent less time studying.

That's the effect of a one-hour difference. Across India, the paper puts the gap in annual average sunset time at about two hours.

Jagnani looked at maths scores from the Young Lives study in Andhra Pradesh, which followed children between 2002 and 2014.

A 10-minute later sunset was associated with maths scores about a tenth of a standard deviation lower.

He also used India's 2015 national health survey to compare children living in the eastern and western parts of the same district.

These weren't experiments in which researchers changed school timings. 

But the findings across the datasets point in the same direction: later sunsets were associated with less sleep and worse educational outcomes.

The paper also discusses the conditions many poorer children sleep in: heat, noise, mosquitoes and overcrowding.

It notes that nearly 75% of India's households live in two rooms or fewer, and cites a separate survey in which nearly three-fourths of children shared a bed. 

Those conditions can make for poorer sleep, but the paper doesn't test them as the reason the penalty is larger.

In Jagnani's 2018 summary of that earlier version, cash running short before harvest explained about a quarter of the sunset effect on sleep for children in farming households.

On paper, an 8 AM bell treats every child the same. The research suggests the cost is uneven: the sleep penalty falls harder on children in the west and on children from poorer homes.

In that earlier version, Jagnani estimated that two time zones, UTC+5 for the west and UTC+6 for the east, could generate about $4.2 billion a year in human-capital gains, around 0.2% of GDP. That's a modelled estimate, not money India is guaranteed to gain, and he called for a fuller cost-benefit analysis.

There is another lever, and it has nothing to do with the clock. In that earlier version, each extra year of exposure to NREGA, India's rural employment scheme, reduced the effect of later sunsets on children's test scores by roughly 10%.

That raises an awkward question for the time-zone debate: if financial constraints make it harder for children to compensate for lost sleep, would moving the clock be enough?

Whether to change the clock is a policy call that needs a proper cost-benefit study. What the research already shows is who has been paying for the current one: children in the west, and poorer children everywhere.

Hit reply and tell me: which city are you in, and what time does your first class or first meeting start?

I read every email.

Until next week,
Ritesh

P.S. Under British rule, India ran on three time zones, and sometimes four.