But for now, it seems like the drawbacks of one time zone do not outweigh the benefits of two. As seen from the tea gardens, early sunrise causes loss of sleep and productivity in locations with less daylight hours, and early sunset can lead to higher energy consumption. There are a few drawbacks of keeping the one time zone. Tea Garden Time, translated as “Chai Bagan Time,” was introduced by the British tea companies to increase daylight work hours and thus productivity and is still in use today. In this part of the country, sunrise can come as early as 4:00 (4 am) IST in the morning and sunset at 16:00 (4 pm) IST in the afternoon. There the clocks are unofficially set one hour ahead of IST (UTC+6:30). Tea Garden Time is an informal time zone used in India's northeastern state Assam. If the country were to base its time zones on mean solar time, it would have three time zones, but since it only has one, the Sun rises almost 90 minutes earlier in Dong in the far east than in Guar Mota in the west.
It spans nearly 30 degrees longitude (68☇'E to 97☂5'E). India is a large country that stretches almost 3000 kilometers (1864 miles) from west to east. However, the UTC+5:30 offset has been used as the local standard time in India since 1906. The country has officially observed India Standard Time (IST) since 1947. Time Zone Currently Being Used in India Offset Business Date to Date (exclude holidays).The DST runs from 2 pm on the 2nd Sunday in March to 2 am on the first Sunday in November. The Daylight Saving Time (DST) is observed in the whole of US states and territories except in Hawaii, Puerto Rico, American Samoa, US Virgin Island, and Arizona (observed only in Navajo Nation). For instance, Howland Island and Baker Island use UTC-12:00 and are sometimes assigned Anywhere on Earth (AoE). The US also possesses outlying islands which do not observe any of the nine time zones. The US territories observe Samoa Time Zone (American Samoa), Atlantic Time Zone (US Virginia Islands and Puerto Rico), and Chamorro Time Zone (the Northern Mariana Islands and Guam). The state of Alaska observes Alaskan Time Zone (UTC-09:00), while Hawaii and parts of the Aleutian Islands have Hawaii-Aleutian Time Zone (UTC-09:00). For instance, Eastern Time refers to EST or EDT. The time zones observed by the 48 states use generic names, without highlighting the difference between DST and standard time designations. The DST is observed in all of the contiguous states except Arizona (observed only in the Navajo Nation). Washington, Nevada, California, and parts of Oregon and Idaho observe Pacific Time Zone (UTC-07:00) while the states straddled by the Rocky Mountains and Great Plains’ western quarter have Mountain Time Zone (UTC-06:00). The second time zone on the contiguous US is the Central Standard Time (UTC-05:00), observed fully by ten states and partly by the other ten states occupying the Mississippi Valley, Gulf Coast, and parts of the Great Plains. However, Indiana, Florida, Kentucky, Tennessee partially use this time zone. All or most of the 23 states in the eastern US, including those on the Atlantic coast, observe Eastern Time Zone (UTC-04:00). These states fall within four time zones. The contiguous US comprises 48 states located within continental North America. The Department of Transportation regulates the DST and time zone boundaries in the US. The contiguous US observes four time zones, while Hawaii, Alaska, and each of the five territories has its time zone. From west to east, the nine US time zones are Chamorro Standard Time (UTC+10), Samoa Standard Time, Hawaii-Aleutian Standard Time (HST), Alaskan Standard Time (AKST), Pacific Standard Time (PST), Mountain Standard Time, Central Standard Time, Eastern Standard Time (EST), and Atlantic Standard Time (AST). By Law, the United States of America and its territories use nine time zones, with most of the county observing DST (daylight saving time) for much of spring, fall, and summer months.