- Ideal World: Every place in the world has a “natural” local time. It can be calculated by multiplying the longitude by 4 minutes. For example, the time at 50°E longitude is 50×4 = 200 minutes, or 3 hours 20 minutes ahead of GMT. The time at 50°W longitude is 3 hours 20 minutes behind GMT.
- Standard Time: However, in the real world, time zones are decided by legislations, DST standards, international conventions, political motives, national convenience, etc. There are usually tolerable “degrees of error” between “natural” time and “assigned/standard” time at a longitude.
- Time zone and Lifestyle: As long as the difference between the “natural” timezone and the “assigned” timezone is very low, there cannot be any role of time zone in affecting the quality of life. (The quality of life, if at all different, may be affected by other reasons such as: climate and latitude or personal timetable choices or culture.) However, when the “natural” timezone and the “assigned” timezone drift largely, lifestyle differences and hence quality of life, do start coming into the picture. Effects like less productivity, social menaces like alcoholism, poverty, etc are possible effects from using politically-designated time zones (explained later in this answer).
1. The Real World Scenario: The Time Zone may affect lifestyle.
In the real world, we do not have the “natural” time zone in several places; this happens when one standard time covers a vast longitudinal expanse. This means that the understanding of every hour of the day may be different for different regions. If a large country like China has just one standard time zone despite the huge longitudinal difference, then:
- the Chinese guy living in Lanzhou (middle of China) understands 12 noon as the time when the sun is atop his head,
- the Chinese guy living in Urumqi (western China) understands 12 noon as the time when the sun is yet to come atop his head,
- the Chinese guy living in Shanghai (eastern China) understands 12 noon as the time when the sun has already crossed his head!
In India, both the westernmost state of Gujarat (at around 68°E) and the easternmost state of Arunachal Pradesh (at around 97°E) observe the same standard time zone: the Indian Standard Time, UTC+5:30. In the ideal world scenario, the time difference between Gujarat and Arunachal Pradesh would have been around 2 hours.
Do you see what this can result in? Read this:
Compared to the rest of India, the eastern States of West Bengal, Bihar, Chhattisgarh, Jharkhand, Orissa, the seven north-eastern States and Sikkim lag in almost all the measures of economic growth. Productivity in these States is low, infrastructure poor and employment opportunities meagre. Overall, the perception is that people of eastern India are lazy and unproductive.[…] Eastern India is blessed with an abundance of mineral wealth — 93 per cent of India’s iron ore, 84 per cent of its coal, 100 per cent of its kyanite, 70 per cent of its mica, 20 per cent of its limestone, 10 per cent of its manganese, 80 per cent of its tea and about 15 per cent of its crude oil.
If this be so, why then are the States of eastern India less productive than the rest of India?
One big possible reason could be the effect of the single time zone. While the natural (ideal) time zone for Gujarat should be around UTC+4:30 and that of Arunachal Pradesh should be around UTC+6:30, both these states are forced to observe UTC+5:30:
Since India has a single time zone, States located to the west of the Indian Standard Time line of longitude (82.5°E) have more daylight hours compared to States located to its east.
The same article goes on to explain plus points of changing the time zone and bringing it closer to the natural time zone:
Some advantages of advancing the clock (in eastern states) would be:
1. Increased productivity: An early start would have more energetic people in the offices.
2. Reduced power consumption: Starting and closing an hour earlier would result in a saving an hour of electricity in offices. In homes, shops and restaurants about two hours would be saved as people would wake up and go to bed earlier, thus using more of the available daylight hours. A conservative estimate shows that starting the day an hour earlier would result in a saving of about 550 MW of power in northeast India alone.
3. Curbing alcoholism: With five to six “available extra hours” after work and with little else to do, most people fall prey to alcoholism.
In continuation to this, also read this one:(an article that proposes, with reasons, the advancement of the IST by half an hour.
The extracts are from this very fine article from The Hindu:.
2. The Ideal World Scenario: Time Zone does NOT affect lifestyle; however there may be other reasons.
What this means: This means that the understanding of every hour of the day is the same all across the world. (If I understand 12 noon as the time when the sun is atop my head, so does everyone else in the world.)
In the map above, I live in Location 1. Hussain lives in Location 2. Emily lives in Location 3. There are no timezone-induced lifestyle differences between Emily, Hussain and me. The reason: all three of us understand time in the same manner, because we all decided our time zones based on our longitudes.
Now, suppose it is prevalent in my culture to wake up at 7 am while Hussain’s culture has most people waking up at 6 am, irrespective of the sunrise. In this case, the quality of life may differ between Hussain and me—but this lifestyle difference is not because of our time zones; it’s because of our cultural differences.
Since I live near the equator while Emily lives near the Antarctic Circle, our maximum sunlight intensities differ; Emily lives in colder conditions, which again means our lifestyles may differ—but it’s not because of time zone, it’s because of our latitudes.