Festival occasions
The 29 festivals that fill the Indian year, from Lohri and Pongal in January to Diwali in autumn, with the date each one falls on this year and what to write to the people who keep it.
Almost every festival here moves. Only a handful, Makar Sankranti among them, are tied to the sun and land on roughly the same date each year. The rest follow a lunar tithi, which is why Diwali, Holi and Ganesh Chaturthi shift by two or three weeks between years, and why a family in Chennai and one in Toronto can mark the same festival a day apart.
How the year clusters
Mid-January brings the harvest festivals, the same days under four names: Lohri in Punjab, Makar Sankranti in the west, Pongal in Tamil Nadu and Magh Bihu in Assam.
Spring carries Holi, then a run of regional new years within a few weeks of each other: Gudi Padwa, Ugadi, Vaisakhi, Puthandu, Pohela Boishakh, Vishu and Bohag Bihu.
Autumn is the heaviest stretch: Onam, Ganesh Chaturthi, Navratri into Durga Puja and Dussehra, then the Diwali week from Dhanteras to Bhai Dooj.
What to write on a festival
Use the name the person actually uses. Deepavali in the south, Kali Puja for a Bengali friend, Saal Mubarak to a Gujarati family the morning after Diwali. Getting the name right does more than any amount of warmth in the wording.
Wishing someone on a festival they don't keep is ordinary courtesy in India, so a friendly greeting to a colleague is almost never wrong. What is worth checking is whether the family has had a death in the past year, since many households skip the first festival after a loss. In that case, write gently and drop the word "happy".