India uses a single time zone, Indian Standard Time (IST), set at UTC+5:30 for the whole country. Clocks never change during the year, so the time in Mumbai, Delhi and Kolkata is always identical — even though the sun rises almost two hours earlier in the north-east than in the far west.
Where these times apply
The whole of India — including the Andaman and Nicobar Islands and Lakshadweep — uses the same time.
One country, one clock
In the decades after independence, Calcutta and Bombay still kept their own local times for a while. Today IST is measured at the 82.5° E meridian near Mirzapur in Uttar Pradesh, roughly in the middle of the country.
In the north-east, where the sun rises very early, there have long been calls for a separate zone. Tea gardens in Assam have traditionally kept an informal ‘garden time’ about an hour ahead of IST, but it has no official status.
Working with India from abroad
India’s difference to Europe and North America changes twice a year — not because India changes its clocks, but because those regions do. The India–UK gap is 5 h 30 min in winter and 4 h 30 min during British Summer Time; India–New York is 10 h 30 min in winter and 9 h 30 min in summer.
Business hours in India
Private offices usually work about 9:30 or 10:00 to 18:00 or 18:30, and many companies also work on Saturdays. Banks close on the second and fourth Saturday of each month as well as on Sundays.
Clock changes in 2026 and 2027
No clock changes in 2026 or 2027: Indian Standard Time.