Calendars of India

A calendar is a system for organising days for social, religious, commercial or administrative purposes. It does this by giving names to spans of time such as the day, week, month and year. India has never used a single calendar. Different regions and communities have reckoned time in different ways, producing dozens of calendars and several distinct eras. An era is a continuous count of years measured from a fixed starting point, called an epoch.

For the exam, three things matter most:

• The three underlying systems of time-reckoning, solar, lunar and luni-solar.
• The main eras, the Vikram Samvat, the Saka Samvat and the Hijri calendar, with their start years and structure.
• The fact that the Saka calendar is the official National Calendar of India.

Every Indian calendar is built on one of three astronomical systems, each based on the movement of celestial bodies.

• Solar year: The time the Earth takes to revolve once around the Sun, returning to the same point of the ecliptic (a solstice or equinox). It runs to 365 days, 5 hours, 48 minutes and 46 seconds and has 12 months. It keeps the closest correspondence between the year and the seasons.
• Lunar year: Also 12 months, but each month (a lunation) is the gap between two successive full moons or new moons. A lunar month runs about 29.5 days. So the lunar year is about 354 days, falling 11 days short of the solar year.
• Luni-solar year: The year is fixed by the solar cycle, but the months follow the lunar divisions, as in the Hindu calendars. The mismatch between the two is corrected by inserting and dropping days and months.

To stop the 11-day gap from pushing festivals and seasons out of place, the lunar and luni-solar systems add an extra month.

• Adhik Masa (also called Mala Masa): An intercalary (inserted) month added roughly every 2.5 years. It brings the lunar year back in line with the solar year. Technically, it is the lunar month in which the Sun enters no new zodiac sign (no Sankranti).
• Kshaya Masa: The opposite case, a month in which the Sun enters two zodiac signs (two Sankrantis), and which is therefore dropped from the count.

A few terms recur across the lunar calendars and are worth fixing:

• Paksha: A fortnight. The Shukla Paksha (bright half) begins the day after the new moon. The Krishna Paksha (dark half) begins the day after the full moon.
• Tithi (or Vasara): The lunar day, averaging about 23 hours 37 minutes, a little shorter than the solar day.
• Divasa: The solar day, one full sunrise-to-sunrise period of 24 hours.
• Amanta and Purnimanta: The two ways of starting a lunar month, either with the day after the new moon (Amanta) or with the day after the full moon (Purnimanta).

The lunar month is the one followed across the greater part of the country.

India's calendars are named after the eras they count from. Three eras dominate.

Vikram Samvat

• Begins about 56 BC, roughly 56–57 years ahead of the Gregorian (Christian) calendar, so its zero year is 56 BC.
• Traditionally said to have been founded by King Vikramaditya of Ujjain to mark his victory over the Saka rulers. Many historians instead link it to the Malawa Ganarajya, hence the older name Malawa Gana era.
• A lunar calendar based on the ancient Hindu calendar, with 354 days in 12 months: Chaitra, Vaisakha, Jyeshtha, Ashadha, Sravana, Bhadrapada, Asvina, Kartika, Margasirsha, Pausha, Magha and Phalguna.
• The new year begins on the first day after the new moon in Chaitra (March–April). In much of India, however, the count of the year starts with Kartika.
• In force across almost all of India except Bengal. In Nepal it begins in mid-April and marks a solar new year.

Saka Samvat

• Begins in 78 AD, near the vernal equinox. It is said to have been initiated by King Shalivahana, after whose tribe (the Sakas) it is named.
• Both solar and lunar in character, with lunar months set inside a solar year. It uses the same 12 month-names as the Vikram era, but they begin at different points.
• A Saka year has a fixed number of days per month and 365 days in all. It starts on 22 March every year, except in Gregorian leap years when it starts on 21 March.
• Months run Chaitra, Vaisakha, Jyeshtha, Ashadha, Shravana, Bhadrapada, Ashwina, Kartika, Margashisha, Pausha, Magha, Phalguna.

Hijri Calendar

• Of Arabic origin and purely lunar, with 12 months and 354 days in a year. The day begins at sunset.
• Originally called Amulfil, it was renamed Hijri (Hejira) after the death of Prophet Muhammad. It commemorates his hijrat (migration) from Mecca to Madina in 622 AD, which became its zero year.
• Because it makes no adjustment to the solar year, its months drift through the seasons. It falls a full year short of the Gregorian calendar every 33 years.
• It was adopted in India under Muslim rule. Of its 12 months, four are sacred: the 1st, 7th, 11th and 12th. Ramadan is the ninth month, observed as a month of fasting.

Two further calendars are useful for comparison:

• Gregorian calendar: A solar calendar reckoned from the birth of Jesus Christ. It starts on 1 January and has 365 days, 5 hours, 48 minutes and 46 seconds. The spare hours are absorbed by adding a day to February every fourth year (the leap year).
• Zoroastrian (Parsi) calendar: Its era began in 632 AD. The Parsis keep two new years, Jamshedi Navroz (around the equinox on 21 March) and the Kadmi new year or Pateti (on 31 August).

The Saka calendar serves as the official civil calendar, the National Calendar of India.

• It was adopted in 1957 on the recommendation of the Calendar Reforms Committee, set up by the Government of India. The Committee standardised the astronomical data and corrected local errors.
• It came into use from 22 March 1957 (Gregorian), which was Chaitra 1, 1879 of the Saka Samvat.
• The aim was to synchronise the roughly 30 different calendars then in use across the country.
• It is used by notification in the Official Gazette, in All India Radio news broadcasts, and in calendars and communications issued by the Government of India. It also helps fix dates of religious significance.