India recognizes three national holidays that are mandatory in all offices, public and private. These are Republic Day (January 26), Independence Day (August 15), and Mahatma Gandhi's Birthday (October 2). It is then up to the state to recognize religious and secular holidays that are used as the basis for private companies and public sector employers.
Holi – Known as the festival of colors, Holi marks the victory of good over evil, the end of the winter season, and the return of Kama to Rati. The most popular part of Holi, Rangapanchami, is when people throw colored powder at each other. Holi falls near spring equinox and is celebrated between three and sixteen days, though no employers offer the latter in vacation days.
Rama Navami – Celebrates the birth of Shri Lord Rama in Ayodhya. The festivities last between one and nine days and are popular in Uttar Pradesh, Andhra Pradesh and Tamil Nadu. His birth occurs on the ninth day of Chaitra month, or very close to the spring equinox.
Krishna Janmashtami – Celebrates the birth of Lord Krishna and is worshipped in all South Indian states.
Ganesh Chaturthi – Celebrates the birth of Lord Ganesha.
Dussehra – Known as Navrathri, the nine nights of celebration of Shakti/Devi during the fall. All states except Punjab celebrate the Dussehra holidays.
Diwali – The largest and most well know Hindu holiday but also celebrated by Jains and Sikhs. Diwali celebrates the victory of good over evil as well as Lakshmi devi, the goddess of light and wealth. Diwali is observed over five days and companies tend to give one to five days of vacation as it is India's largest holiday.
Day of Ashura – Marks the martydom of Husayn ibn Ali, on the tenth day of Muharram. This holiday is observed in India by the Shia Muslim population and many states give the day off as a public holiday.
Eid ul-Fitr – The most famous Islamic holiday, Eid ul-Fitr, marks the end of the Ramadan fasting period and is celebrated for three days.
Eid al-Adha – Known as the Greater Eid, Eid al-Adha marks the sacrifice Abraham's son to God and God's gift of a ram in lieu of the son's sacrifice. The three-day celebrates occurs in November during the last month of the Islamic calendar.
Other religious holidays
Mahavir Jayanti – Celebrates the birth of Lord Mahavir in Jain religion. His birthday is celebrated during the springtime (late March – April) depending on the calendar.
Nowruz – The Parsi New Year celebrated in the summertime in Indian. In Iran, Nouraz is celebrated during the spring equinox.
Guru Nanak Jayanti – The celebration of the birth of the first Sikh guru, Guru Nanak. Most popular in Punjab, where the largest contingent of Sihks live, and fourteen states in India. The holiday is celebrated on November 21st.
Non-religious holidays includes New Year's Eve and New Year's Day and many state days. State days include Maharastra Day, Gujarat Day, Kerala Foundation day among others and are celebrated exclusively by the state in which the holiday represents.