India's single time zone is a legacy of British rule, and is thought of as a symbol of unity. But not everyone thinks the Indian Standard Time (IST) is a good idea.
India stretches 3,000 km (1,864 miles) from east to west, spanning roughly 30 degrees longitude. This corresponds with a two-hour difference in mean solar times – the passage of time based on the position of the sun in the sky.
The US equivalent would be New York and Utah sharing one time zone. Except that in this case, it also affects more than a billion people – hundreds of millions of whom live in poverty.
The sun rises nearly two hours earlier in the east of India than in the far west. Critics of the single time zone have argued that India should move to two different standard times to make the best use of daylight in eastern India, where the sun rises and sets much earlier than the west. People in the east need to begin using their lights earlier in the day and hence use more electricity, says a BBC.com feature. People from the west visiting the east are taken by surprise when dusk falls so early.
The rising and setting of the sun impact our body clocks or circadian rhythm. As it gets darker in the evening, the body starts to produce the sleep hormone melatonin, which helps people nod off.
In a new paper, Maulik Jagnani, an economist at Cornell University, argues that a single time zone leads to a decline in quality of sleep, especially of poor children. This, he says, ends up reducing the quality of their education.