UTC vs IST — cities and working rhythm
UTC is the reference offset — not a civil timezone anywhere, but the standard for aviation ("Zulu time"), server logs, astronomy, and cross-timezone team calendars. When distributed engineering teams schedule "the daily standup at 15:00 UTC" they're dodging the DST-flip mess entirely.
Indian business hours run 10 AM – 7 PM IST typically; IT / BPO shifts commonly extend to cover US and UK working hours, so 3:30 PM – 12:30 AM IST (US overlap) and 12:30 PM – 9 PM IST (UK overlap) are the two second shifts you see most often. Weekend is Saturday-Sunday for most private-sector employers.
Time gap: IST is 5.5 hours ahead of UTC (standard-time offsets — daylight-saving flips shift this by an hour twice a year in most northern-hemisphere zones).